Health Hazard Evaluations: TuberculosisHealth Hazard Evaluations: Tuberculosis 1990 to 1999 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Centers for Disease Control

Health Hazard Evaluations:

Tuberculosis1990 to 1999

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICESPublic Health Service

Centers for Disease Control and PreventionNational Institute for Occupational Safety and Health

TM

DisclaimerForewordContributing OfficersHealth Care FacilitiesDrug Treatment FacilitiesSocial ServicesCoroner's OfficeCorrectional FacilitiesLaboratoryHomeless SheltersOther Facilities

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National Institute for Occupational Safety and Health

Health Hazard Evaluations:Tuberculosis1990 to 1999

U.S. DEPARTMENT OF HEATH AND HUMAN SERVICESPublic Health Service

Centers for Disease Control and PreventionNational Institute for Occupational Safety and Health

January 2001

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Mention of any company or product does not constitute endorsement by the National Institute forOccupational Safety and Health.

This document is in the public domain and may be freely copied or reprinted.

To purchase individual published reports listed in this document or to order the CD-ROM collectionof selected published Health Hazard Evaluation Reports from 1980 to 1996, contact the NationalTechnical Information Service as follows:

National Technical Information Service5285 Port Royal RoadSpringfield, VA 22161

1–800–533–NTIS (1–800–533–6847)www.ntis.gov

To order single copies of closeout letters and final reports listed in this document, please send yourrequest (including the HETA reference number) and a self-addressed, stamped envelope to theHazard Evaluations and Technical Assistance Branch (HETAB) as follows:

National Institute for Occupational Safety and HealthHazard Evaluations and Technical Assistance Branch

4676 Columbia Parkway, R–9Cincinnati, OH 45226–1998

1–513–841–4252www.cdc.gov/niosh/hhe

To make general inquiries about any of the reports contained in this document, call the TB ProjectOfficer, HETAB, at 1–513–841–4374.

To receive information about other occupational safety and health topics, call 1–800–35–NIOSH(1–800–356–4674), or visit the NIOSH Web site at www.cdc.gov/niosh.

DHHS(NIOSH) Publication No.2001–116

Disclaimer

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The Health Hazard Evaluations and Technical Assistance (HETA) Program responds to requests from em-ployers, employees, employee representatives, other Federal agencies, and State and local agencies. Througha staff of industrial hygienists, engineers, occupational physicians, epidemiologists, other health professionals,and support personnel, the Hazard Evaluations and Technical Assistance Branch (HETAB) collaborates withappropriate personnel in other divisions of the National Institute for Occupational Safety and Health (NIOSH)to respond to approximately 400 requests for assistance each year. The typical HETA response to a requestfor assistance results in (1) an evaluation of whether chemical, physical, biological, or other agents arehazardous as used or found in the workplace and (2) the development of recommendations for control proce-dures, improved work practices, and medical programs to reduce exposure levels and prevent adverse healtheffects. The results of individual evaluations may trigger wider studies of similar exposures in other settingsor may stimulate recommendations for implementation or modification of health standards. More than 10,000evaluations have been completed since the inception of the HETA Program in 1972. Requests received by theHETA Program tend to reflect emerging occupational problems, such as tuberculosis (TB) in the workplaceand other National Occupational Research Agenda (NORA) priority areas.

The TB-related Health Hazard Evaluation (HHE) Project administers HHEs of occupational exposure to TB.Site visits are conducted if warranted, and interim and final reports are developed and distributed to theemployer, employees, and relevant State and Federal agencies. Seventy-seven TB-related HHEs were re-quested from 1990 to 1999. The HHE requests came from a variety of workplaces, including hospitals,neighborhood health centers, TB clinics, homeless shelters, drug treatment centers, correctional facilities,social service facilities, laboratories, medial waste treatment facilities, and an inspection station for importednon-human primates.

This document presents titles and summaries of HHEs related to TB, organized by type of facility. In mostcases TB exposure was just one of several exposures that NIOSH researchers investigated at a work site. Inmany cases, corrective measures were made in response to the evaluation and recommendations made byNIOSH investigators.

Lawrence J. Fine, M.D., Dr..P.H.Acting DirectorNational Institute for Occupational Safety and Health

Foreword

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Contributing Project OfficersFaye T. Bresler, M.D., M.P.H.Yvonne Boudreau, M.D., M.S.P.H.Teresa M. Buchta, M.S.Nancy Clark Burton, M.P.H., M.S., C.I.H.Michael S. Crandall, M.S., C.I.H.John A. Decker, M.S., C.I.H.Scott Deitchman, M.D., M.P.H.Richard Driscoll, Ph.D.Charles S. Hayden II, B.S.Edward Hoekstra, M.D.Robert T. Hughes, Ph.D., P.E.Paul Jensen, Ph.D., P.E., C.I.H.John Kelly, M.S.Matthew Klein, P.E.Greg J. Kullman, Ph.D., C.I.H.Charles S. McCammon, Ph.D., C.I.H.Kenneth F. Martinez, M.S.E.E., C.I.H.Aubrey Miller, M.D., M.P.H.

Vincent Mortimer, P.E.C. Eugene Moss, H.P., C.S.S.Lee Petsonk, M.D.Teresa A. Seitz, M.P.H., C.I.H.Ruth A. Shults, R.N., M.P.H.William K. Sieber, Ph.D.David Sylvain, M.S., C.I.H.Allison Tepper, Ph.D.Douglas B. Trout, M.D., M.H.S.Randy L. Tubbs, Ph.D.Angela M. Weber, M.S.

Edited by:Jane Weber, M.Ed.Teresa A. Seitz, M.P.H., C.I.H.

Desktop Publishing by:Donna M. Pfirman

NIOSH Printing Office:Penelope ArthurShirley Carr


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HETA 90–0122–2073October 1990

Purpose: To investigate potential occupationalhazards related to germicidal lamps used todisinfect the air in tuberculosis (TB) andaerosolized pentamidine (AP) clinics.

Keywords: SIC* 8011 (Offices and Clinics ofDoctors of Medicine) and 8071 (MedicalLaboratories), TB, skin testing, ventilation.

Abstract: Because of concerns regarding theultraviolet (UV) exposure in this hospital andmedical center, an evaluation was undertaken ofpossible hazardous working conditions at thatsite. Concern existed about exposures to hazardswhile operating the germicidal lamps at thisfacility. Germicidal lamps were used to disinfectthe air in TB and AP clinics. All rooms used a30-watt germicidal lamp. Lower wattage bulbsin the smaller rooms would have reduced occu-pational UV exposure. Reflectance levels of UVradiation were quite high and varied. Workerexposure to germicidal lamp UV levels wasdependent on many factors, some of the mostimportant ones being the position of the bulb inthe room, age of the bulb, obstruction of the UVradiation by objects near the bulb, and the heightof the worker. While no consensus guidelinesare available on ventilation systems designed forareas where germicidal lamps are used, theprovision of good room air distribution andmixing is recommended to prevent stagnant airconditions or short circuiting of supply air withinthe room. Bulb changers need to be aware of theneed for protective clothing and gloves forprotection from both the UV radiation levels aswell as possible glass breakage.

Copies are available from HETAB.†

HETA 90–0330–2479December 1994

Purpose: To evaluate occupational exposure toaerosolized pentamidine (AP) and purifiedprotein derivative (PPD) skin test conversionamong employees administering AP treatments.

Keywords: SIC 8069 (Specialty Hospitals, ExceptPsychiatric), pentamidine, pentamidineisethionate, AP, tuberculosis (TB), health careworker, human immunodeficiency virus (HIV),Pneumocystis carinii pneumonia.

Abstract: NIOSH representatives conducted healthhazard evaluations at four hospitals to evaluateexposures to AP and to determine whetherworkers administering AP were at increased riskof occupational TB transmission. The NIOSHevaluations included air sampling for pentami-dine during AP administration and a review ofemployee health records to assess the rate of TBPPD skin test conversion. The exposed respon-dents indicated that they gave an average of11 pentamidine treatments per week (range 0 to20). None of the employees who were PPD skintest negative before administrating AP hadconverted to PPD positive on their most recenttest. However, the most recently reported testsfor three employees had been administered morethan 1 year previously (ranging from 12 to 18months). Personal breathing zone concentrationsof pentamidine ranged from non-detectable to46 µg/m3 . Local exhaust ventilation was effec-tive in minimizing environmental contaminationand worker exposures to pentamidine and wouldalso serve to reduce exposures to Mycobacte-rium tuberculosis (M. tuberculosis) if present inthe environment. Recommendations to furtherreduce workers’ exposures to AP and to M.tuberculosis while caring for HIV-infectedpatients and to improve medical surveillanceprograms for PPD skin test conversion arecontained in the full report.

Copies are available from NTIS,‡ individually oron CD-ROM.

Health Care Facilities

*Standard Industrial Classification†Hazard Evaluations and Technical Assistance Branch ‡

National Technical Information Service

2National Institute for Occupational Safety and Health

HETA 90–0350January 1991

Purpose: To evaluate the ventilation systems,work practices, and administrative procedures atthis hospital in conjunction with a separateinvestigation of possible nosocomial transmis-sion of tuberculosis (TB).

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, aerosolized pentami-dine (AP), ventilation system, health careworkers.

Abstract: The NIOSH evaluation focused on an inpatient Acquired ImmunodeficiencySyndrome (AIDS) unit and a special immunologyclinic that performed AP administration and sputuminduction. A ventilation system evaluation wasperformed that included measurement of thevolume rate of air flow, the direction of airflow, andquantitative determinations of air pressure differen-tial between inside the patient rooms and thecorridors. Air change rates were calculated from theair flow rate data and were compared with existingguidelines. On the AIDS unit, approxi-mately one-fourth of the patient rooms allowed air to flow outinto the corridor (i.e., they were under positivepressure), and more than half of the rooms had aninsufficient supply of outside air. The specialimmunology clinic, the pentamidine administrationrooms, main treat-ment room, and several examina-tion rooms were under positive pressure and had aninsufficient supply of outside air. Air recirculationalso existed in the main treatment room and severalexamination rooms which allowed the intro-ductionof infectious aerosols escaping from the pentami-dine room into these areas. Based on the history ofwork practices and administrative controls and onthe results of the NIOSH evaluation, there waspotential for employee exposure to infectiousmicroorganisms in the evaluated areas. Recom-mendations were made to correct the ventilationdeficiencies and other procedural problems identi-fied in the NIOSH evaluation.

Copies are available from HETAB.

HETA 91–0148–2236July 1992

Purpose: To investigate exposure toultraviolet (UV) radiation emitted by germi-cidal lamps at a tuberculosis (TB) clinic.

Keywords: SIC 8099 (Health and AlliedServices, Not Elsewhere Classified), germi-cidal ultraviolet (GUV) radiation, TB clinic,ventilation.

Abstract: NIOSH representatives providedassistance in documenting occupationalexposure to UV radiation emitted by germi-cidal lamps at this TB clinic. NIOSH person-nel made GUV radiation measurements on alllamps at the TB clinic. The results of thisevaluation showed that the levels of occupa-tional exposure to GUV radiation produced inmost of the work areas were below the NIOSHrecommended exposure limit (REL) of 0.1effective µW/cm². The only exceptions foundwere GUV levels at very close distances tolamps. Other findings noted were the presenceof old lamps, inappropriate labeling andposting of signs, and ventilation deficienciesin the TB clinic area. Based on GUV radiationmeasurements, it was determined that a healthhazard could exist from exposure to thegermicidal lamps at a distance of 10.2 cm orcloser if workers did not wear protectiveeyewear. Except for one situation, exposure toGUV at distances greater than 10.2 cm did notrepresent a health hazard on the day of mea-surement. Recommendations for minimizingthe UV exposures as well as improving certainventilation parameters were provided.

Copies are available from NTIS, individuallyor on CD-ROM.


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HETA 91–0187–2544November 1995

Purpose: To investigate nosocomial transmissionof tuberculosis (TB) in health care workers.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, aerosolized pentami-dine (AP) isethionate, aerosolized pharmaceu-ticals, respirators, ventilation system, aerosolcontainment system, health care workers,ultraviolet (UV) radiation, germicidal lamps.

Abstract: A health hazard evaluation was con-ducted by NIOSH researchers at this hospitalto assess nosocomial transmission of TB inhealth care workers. NIOSH investigatorsevaluated the risk of tuberculin skin test (TST)conversion in employees exposed to patientswith infectious TB, the adequacy of ventilationin areas of the hospital where patients withinfectious TB are treated, the potential forexposure to AP and to Mycobacterium tuber-culosis in workers who administered AP, andthe potential for overexposure to ultravioletgermicidal irradiation (UVGI) from UV lamps.The risk of TST conversion was evaluatedthrough a 4-year retrospective cohort studyamong exposed (n=249) and unexposed(n=355) employees. Employees who workedin areas where patients with active TB werecared for, including workers who did notprovide direct patient care, had a higher rate ofTST conversion than employees who did notwork in these areas. A decline in this elevatedrisk was seen over time. Reasons for thedecline include outbreak termination, feweradmissions of TB patients, implementation ofeffective infection control measures, andpossible resistance to infection in some mem-bers of the study population. Some hospitalareas where patients with infectious TB arecared for had inadequate ventilation. Workerswho administered AP treatments to patientshad no increase in symptoms or risk of TB

infection over workers who did not administerthese treatments. The potential for overexpo-sure to UV radiation existed for those whoworked around functioning UVGI lamps.Recommendations addressing each of theseissues are provided in the full report.

Copies are available from NTIS, individuallyor on CD-ROM. The study was published inthe American Journal of Industrial Medicine.(Boudreau AY, Baron SL, Steenland NK,VanGilder TJ, Decker JA, Galson SK, andSeitz T. [1997] Occupational Risk of Myco-bacterium tuberculosis Infection in HospitalWorkers. Am J Ind Med 32: 528-534.)

HETA 92–0215–2268November 1992

Purpose: To investigate the potential for tuber-culosis (TB) transmission at this TB hospital.

Keywords: SIC 8069 (Specialty Hospitals,Except Psychiatric), TB, state hospital, venti-lation, infection control.

Abstract: NIOSH investigators performed ahealth hazard evaluation (HHE) that includedindustrial hygiene and medical components ata state TB hospital. The industrial hygienecomponent focused on assessing the effective-ness of the ventilation systems in use at thehospital. A visual inspection of the ventilationsystems and a review of the original specifica-tions of the air-handling units were completedby the investigators. Additionally, measure-ments were made of the airflow from supplyand exhaust diffusers in patient rooms, alongwith temperature and relative humidity mea-surements. The direction of airflow betweenpatient rooms and hallways and betweenhospital wards was also determined in severallocations in the hospital complex. The medicalcomponent consisted of a qualitative review ofcurrent employee infection control practices.Some deficiencies were noted in the ventila-


tion systems that could potentially contributeto the transmission of TB from infectiouspatients to other patients and hospital staff.Recommendations to modify the ventilationsystems to meet isolation evaluation criteriaare contained in the full report along withrecommendations to strengthen the hospital’semployee skin testing and infection controlprograms.


HETA 92-0232-2767November 1999

Purpose: To evaluate the risk of transmission ofMycobacterium tuberculosis (M. tuberculosis)to hospital workers.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), tuberculosis (TB), hospi-tal workers, occupational exposure, nosoco-mial transmission, tuberculin skin test.

Abstract: NIOSH investigators conducted anepidemiologic study of the risk of M. tubercu-losis transmission (as defined by tuberculinskin test [TST] conversion) among hospitalworkers with “patient contact” compared toworkers with “no patient contact.” Hospitalworkers employed at the hospital from Janu-ary 1, 1990, through September 30, 1992 wereincluded in the retrospective cohort study.Personal, community, and occupational riskfactors for TST conversion were evaluated in2,362 workers with potential tuberculosisexposure and 886 workers with little or nopotential for exposure. Among workers withpotential exposure, statistically significantlyelevated risks for TST conversion were foundfor nurses, phlebotomists, emergency roomworkers, housekeepers, clerks, and emergencyresponders. Among nurses, the risk wasrelated to a proxy measure of occupational TB

exposure (i.e., the number of positive M.tuberculosis cultures from their work loca-tion).

Copies are available from NTIS.

HETA 92–0296–2243August 1992

Purpose: To determine if ventilation require-ments for the isolation of tuberculosis (TB)patients were being met at this medical center.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, ventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this medical centerto evaluate the ventilation systems in aninfectious disease ward. NIOSH investigatorsmade ventilation measurements to determinethe status of the ventilation systems servingthe area. Smoke tube traces were used todetermine room-to-corridor pressure relation-ships and the pressure relationship of theinfectious disease ward to the core areas of thehospital. There was a general flow of air out ofthe infectious disease ward and into the corearea. In fact, the air flowed through the corearea and into an adjacent wing of the hospital.This condition could cause the circulation ofinfectious agents to other wards and floors ofthe hospital because of shared heating, venti-lating, and air conditioning (HVAC) systems.On the basis of the measurements made duringthe evaluation, there was no apparent isolationof infectious patients in the infectious diseasesward. It was recommended that a separateisolation facility be constructed in the hospitalto house infectious TB patients. Interimcorrective measures for the systems in placewere also recommended.



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HETA 92–0298–2325June 1993

Purpose: To investigate the ventilationsystems serving the isolation rooms fortuberculosis (TB) patients in six hospitals.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, ventilation, infectioncontrol.

Abstract: NIOSH investigators conducted ahealth hazard evaluation to evaluate theventilation systems serving the isolationrooms for TB patients in six hospitals. Avisual inspection of the ventilation systems, aswell as a review of the original specificationsof the air-handling units, was completed foreach facility. Where the ventilation systemswere operating, airflow measurements fromsupply and exhaust diffusers were made.Smoke tube traces were used to determineroom-to-corridor pressure relationships.General information was gathered on em-ployee tuberculin skin testing programs. Somedeficiencies were noted in the ventilationsystems of these facilities that could poten-tially contribute to the transmission of TBfrom infectious patients to other patients,hospital staff, and visitors. Recommendationsto modify the ventilation systems so thatisolation evaluation criteria are met wereoffered in the full report, along with recom-mendations to strengthen the infection controlprograms at the facilities.


HETA 93–0046March 1995

Purpose: To investigate the collection of envi-ronmental air samples for Mycobacteriumtuberculosis (M. tuberculosis).

Keywords: SIC 8069 (Specialty Hospitals,Except Psychiatric), tuberculosis (TB), statehospital, ventilation, infection control.

Abstract: This research was conducted to test anexperimental methodology for collectingenvironmental air samples for M. tuberculosis.This hospital was selected for this experimen-tal study design based on the number of activeTB patients resident at any given time. Eightyculturable air samples were collected invarious locations throughout the hospitalincluding three patient rooms and two controllocations. Subsequent analysis of sampleplates revealed no acid-fast bacilli. Numeroustheories exist about to the inability to cultureM. tuberculosis from the air including theappropriateness of the sampling method andthe fastidiousness of the organism. However,the infectious nature of the patients was notsuspected as a limiting factor considering thatat least one of the patients was identified assputum smear positive one day prior to thesampling efforts.



HETA 93–0652November 1997

Purpose: To investigate occupational exposuresto Mycobacterium tuberculosis (M. tuberculo-sis) at a medical center.

Keywords: SIC 8062 (General Medical andSurgical Hospitals) tuberculosis (TB), medicalcenters, ventilation, ultraviolet lamp.

Abstract: NIOSH investigators conducted anenvironmental assessment regarding occupa-tional exposures to M. tuberculosis at a de-partment of this medical center. The assess-ment was conducted as a result of an epide-miologic investigation of suspected nosoco-mial transmission of multidrug-resistant M.tuberculosis at the facility in 1992. NIOSHpersonnel conducted an evaluation of themedical center, examined the ventilationsystems serving the isolation and treatmentrooms, and evaluated germicidal ultravioletlamps that were used as environmental con-trols. The ventilation system evaluationincluded discussions with persons responsiblefor operation and maintenance of the systemand performance of airflow measurements.Some of the isolation rooms operated underpositive pressure at all times with respect tosurrounding areas. Specific recommendationsregarding the ventilation system and ultravio-let lamps evaluated during the survey wereoffered in the closeout letter.


HETA 93–0746 and 93–0747August 1995

Purpose: To investigate the potential for occu-pational exposure to Mycobacterium tubercu-losis among employees in county health carefacilities.

Keywords: SIC 8093 (Specialty OutpatientFacilities, Not Elsewhere Classified), tubercu-losis (TB), ventilation, tuberculin skin testing.

Abstract: NIOSH investigators examined theairflow between rooms and hallways, and thestatus of the germicidal ultraviolet lampcontained in the facility nebulizer room.Inspection of the air handling systems re-vealed no general maintenance problems.Investigators found that the close proximitybetween the outdoor air intake and systemexhaust could lead to reintrainment of ex-hausted air back into the system and subse-quently, the occupied spaces. The ultravioletbulb was dust-covered, potentially rendering itless effective as an air disinfectant. Employeesin the health clinics serve patients with sus-pected or active TB at the clinics or at thehomes of the patients. Results from the envi-ronmental investigation indicate that theventilation systems in both buildings wererecirculating with a common return air plenumthat could increase the potential risk of TBtransmission into other areas of the buildings.Recommendations were offered to help theclinics improve their work environments andpotentially reduce the risk of TB transmission.



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HETA 93–0770February 1996

Purpose: To evaluate the effectiveness ofthe ventilation systems for preventing tubercu-losis (TB) transmission at this outpatient TBclinic.

Keywords: SIC 8099 (Health and AlliedServices, Not Elsewhere Classified), tubercu-losis, sputum induction, ventilation system,outpatient clinic, health care workers, purifiedprotein derivative skin test, respirator.

Abstract: NIOSH investigators conducted anevaluation at this outpatient TB clinic to assistthe facility in determining the best location fora future TB isolation room and to determinethe operational status of the ventilation sys-tems serving the areas of concern. Visualinspections were made of the general ventila-tion system and the local exhaust ventilation(booth) used for sputum inductions. Thedirection of air flow between rooms andadjacent areas was determined using smoketubes. Deficiencies identified during theenvironmental evaluation that may increasethe risk of TB transmission included the lackof an isolation room, recirculation of airthroughout the facility, insufficient use ofrespiratory protection, and problems withoperation of the sputum collection booth.Recommendations were made to correct thenoted deficiencies and improve the overall TBprevention program at this facility.


HETA 93–0772July 1995

Purpose: To investigate the potential for tuber-culosis (TB) transmission in a neighborhoodhealth center.

Keywords: SIC 8011 (Offices and Clinics ofDoctors of Medicine) and 8071 (MedicalLaboratories), TB, skin testing, ventilation.

Abstract: Because of concerns regarding thepotential for TB transmission in the facility,NIOSH was asked to evaluate a neighborhoodhealth center and make recommendationsregarding TB infection-control procedures.NIOSH representatives conducted a site visit toreview the tuberculin skin testing program,determine the operational status of the ventila-tion system, and review ventilation plans andspecifications for the new addition to the build-ing which was under construction at the time ofthe survey. On the basis of a review of theblueprints of the facility and a walk-throughinspection, several rooms in the new additionwere chosen as future isolation rooms because oftheir location within the facility and the ability tooptimize the ventilation rates of the rooms.NIOSH investigators found that although thefacility had implemented a comprehensivescreening program for employees, engineeringcontrol deficiencies and the lack of appropriaterespiratory protection may increase the risk ofMycobacterium tuberculosis (M. tuberculosis)transmission in the facility. Since most of theareas of the existing building recirculate all roomair, a potential to spread M. tuberculosisthroughout the facility existed whenever a clientwith active TB entered the clinic. Additionally,the inappropriate use of a chemical fume hoodfor the preparation of TB specimens may poseadditional risks to employees. Recommendationsbased on current Centers for Disease Control andPrevention guidelines are offered in the report.



HETA 93–0780March 1996

Purpose: To investigate the tuberculosis (TB)prevention program, work practices, andengineering controls at this hospital.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, ventilation, skin test,Centers for Disease Control and Prevention.

Abstract: NIOSH investigators conducted ahealth hazard evaluation to review the TBprevention program, work practices, andengineering controls within this hospital. Theinvestigation was prompted by concerns aboutseveral purified protein derivative (PPD) skintest conversions among personnel in theIntensive Care Unit (ICU). The TB infection-control program and administrative proceduresand policies were reviewed with hospitalrepresentatives. Also, a limited ventilationevaluation was conducted in several regularpatient rooms, treatment rooms, and roomsdesignated for TB isolation. The ventilationevaluation revealed a need to increase the airchanges per hour (ACH) in the ICU. Also, aneed for improved respiratory protectiondevices and a complete respirator programwere needed. On the basis of updated Centersfor Disease Control and Prevention guidelines,NIOSH investigators made specific recom-mendations about the employee purifiedprotein derivative (PPD) skin testing program,procedures for handling infectious patients,use of respiratory protection, engineeringcontrols, and the bacteriology laboratory’sprocedures for processing sputum samples.


HETA 93–0950May 1997

Purpose: To investigate the effectiveness of thetuberculosis (TB) control program at thismedical center.

Keywords: SIC 8062 (General Medical andSurgical Hospitals), TB, health care, hospital,infection control.

Abstract: NIOSH personnel conducted a healthhazard evaluation of the TB control programat this medical center. Environmental evalua-tions were conducted at two hospitals. Theevaluations focused on areas where exposureto Mycobacterium tuberculosis would mostlikely occur. Discussions were held withrepresentatives from Infection Control, PlantServices, Respiratory Services, and the Labo-ratory. A limited ventilation evaluation wasconducted in selected areas, including mea-surements of exhaust airflow and an assess-ment of airflow direction. A 1997 site visitincluded a walk-through survey of the hospi-tals. Observations of smoke tube traces weremade to evaluate the direction of airflow incertain locations. Discussions were held withthe infection control specialist and a unitnurse. A copy of the revised TB ControlPolicy and Procedures Manual was obtainedfor review. Since the initial NIOSH visit in1994, several improvements occurred in theTB Control Program. These changes andNIOSH recommendations for other improve-ments to the tuberculin skin test screeningprogram and ventilation systems are presentedin the closeout letter.



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HETA 93–0845–2367, 93–0846–2386,93–0751–2408, 93–0847–2384, and93–0848–2399November 1993 to March 1994

Purpose: To investigate the effectivenessof ventilation systems in reducingtuberculosis (TB) transmission in healthcare center facilities.

Keywords: SIC 8011 (Offices and Clinics ofDoctors of Medicine), TB, ventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation to assess the ventila-tion systems at several health care centers,especially in regard to the suitability of thesesystems for minimizing TB transmission. Avisual inspection of the ventilation systems, aswell as a review of the original specificationsof the air-handling units, was completed forthe centers. Smoke tubes were used to deter-mine pressure relationships between examina-tion rooms and corridors. A number of prob-lems were observed with respect to the opera-tion and maintenance of the ventilation sys-tems that could potentially increase the risk ofTB transmission in areas where TB patientsmight be present. Heating, ventilating, and air-conditioning units were operated in an auto-matic mode that resulted in no air beingsupplied to examination rooms and laborato-ries when temperature set-points were satis-fied. The clinics had established a tuberculinskin test screening program for clients but hadno program for employees. Recommendationsto correct deficiencies in the ventilationsystem and TB control program are offered inthe full report.


HETA 96–0192August 1996

Purpose: To investigate engineering controlsplanned for two county tuberculosis (TB)clinics.

Keywords: SIC 8093 (Specialty OutpatientFacilities, Not Elsewhere Classified), TB,clinic, respirator.

Abstract: NIOSH representatives conducted ahealth hazard evaluation to provide assistancein evaluating engineering controls planned fortwo county TB clinics. To prevent TB trans-mission from patients with unknown orunrecognized active TB, the county hadcommitted to renovating two existing medicalfacilities where TB clinics are held. NIOSHvisited the two facilities to determine if theproposed control measures were necessary andadequate for preventing TB transmission.NIOSH representatives met with personnelfrom the county’s environmental health,nursing, and engineering departments todiscuss ventilation requirements, use ofgermicidal ultraviolet radiation lamps, tuber-culin skin testing, and use of respirators andportable high efficiency particulate air(HEPA) filtration units. Following this meet-ing, NIOSH representatives toured the areaswhere the current TB clinics were held as wellas the area that was being renovated for futureuse at the facility. At both facilities, routineTB skin testing of clients was provided alongwith TB skin testing of suspect TB cases andclose contacts of persons known to have activeTB. The medical staff also provided X-raysand medical exams, and sputum samples weresometimes collected from persons suspectedof having active TB. Surgical masks wereprovided to patients who may be infectious,and staff wore NIOSH-approved disposableHEPA respirators when treating or examining


potentially infectious TB patients. On thebasis of a facility tour and discussions withcounty health department personnel, theNIOSH investigators supported their efforts toconsolidate TB-related activities and to im-prove engineering controls at both facilities.NIOSH recommendations are included in thefull report.


HETA 93–0365–2421May 1994

Purpose: To investigate the administrative andengineering control measures that are used toreduce potential exposures to tuberculosis(TB) in an outpatient methadone maintenanceand detoxification center.

Keywords: SIC 8093 (Specialty OutpatientFacilities, Not Elsewhere Classified), drugtreatment center, methadone, TB, tuberculinskin test (TST), ventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this outpatientfacility to investigate potential TB transmis-sion due to contact with a client population athigh risk for TB. NIOSH investigators re-viewed the facility’s written TST program andtesting results and conducted informal inter-views with employees. A visual assessment ofthe ventilation and airflow patterns wasperformed, and random measurements of thesupply airflows were made. The investigatorsfound that of the 55 employees, three personsconverted to a positive skin test during theiremployment. As information about the dura-tion of employment was not fully available,NIOSH investigators were unable to calculatethe incidence of positive skin tests among all

employees. Investigators found that the venti-lation system within the center recirculated100% of the air and is therefore not an effec-tive engineering control for reducing exposureto TB. It was determined that a potentialhazard existed for health care workers at thisfacility who were exposed to clients withactive TB. Recommendations were made inthe report to improve the ventilation systems,use appropriate personal protective equipment,and improve the TST program.


HETA 92–0271–2349September 1993

Purpose: To investigate the potential fortuberculosis (TB) transmission at a paroleoffice building.

Keywords: SIC 8322 (Individual and FamilySocial Services), parole office, TB.

Abstract: NIOSH investigators conducted anevaluation of the ventilation system in thisparole office to assess air distribution, outsideair intake and dilution. NIOSH researchersmeasured outside airflow and carbon dioxide(CO2) concentrations, a surrogate indicator ofoutside airflow into a building, and adminis-tered questionnaires to employees. Outside airintake on the first floor (and possibly the thirdfloor) did not meet the American Society ofHeating, Refrigerating, and Air-ConditioningEngineers (ASHRAE) ventilation recommen-dations for office space. Parole board employ-ees may have had an added risk of TB infec-tion because (1) parolees are at increased riskfor developing active TB (all have beenincarcerated, some are medically underserved,

Social Services

Drug Treatment Facilities


11

and some are homeless) and (2) the ventilationsystem recirculated most of the air in thefacility, thereby permitting any infectiousdroplet nuclei in the air to spread throughoutthe facility. Recommendations for an em-ployee TB screening program and improve-ments to the ventilation system were providedin the full report.



Purpose: To investigate the potential for occu-pational exposure to Mycobacterium tubercu-losis (M. tuberculosis) among social servicesemployees.

Keywords: SIC 8093 (Specialty OutpatientFacilities, Not Elsewhere Classified), tubercu-losis (TB), tuberculin skin test (TST).

Abstract: NIOSH investigators conducted ahealth hazard evaluation to assess the potentialfor occupational exposure to M. tuberculosisamong county social services employees.NIOSH conducted a TST program amongthese county employees. One hundred forty-eight employees participated in the initialTST. In the follow-up TST program, oneperson converted to a positive skin test out ofa total of 78 who completed the study. Thelow participation rates for the study preventeddrawing any definitive conclusions regardingthe risk of occupational transmission of TBamong employees. A recommendation wasmade to continue the skin testing program forthose workers who are potentially occupation-ally exposed to TB.


HETA 93–0891–2430June 1994

Purpose: To investigate the potential risk oftuberculosis (TB) transmission to socialservice employees at three sites.

Keywords: SIC 9441 (Administration of Social,Human Resource and Income MaintenancePrograms), TB, social service, welfare, indoorair quality, indoor environmental quality.

Abstract: NIOSH representatives conducted ahealth hazard evaluation of several socialservice offices to determine (1) whetheremployees can reasonably anticipate risk ofexposure to TB, and (2) what engineering andadministrative controls should be recom-mended for social service settings. NIOSHinvestigators assessed the ventilation systemof the food stamp office and conducted amedical evaluation of employees at all threesites. The environmental evaluation indicatedthat the air handling units were not supplyingsufficient outdoor air (for dilution ventilation)on the day of measurement. The medicalevaluation included confidential interviewswith 18 workers and a review of the methodsand results of a voluntary TB screening.Because of sample size, the results of thisscreening effort may not represent the actualprevalence of tuberculous infection. Recom-mendations for an employee TB education andscreening program for Division of Welfareemployees and for improvements to theventilation system in the food stamp officewere provided in the full report.



HETA 96–0233September 26, 1996

Purpose: To investigate potential transmissionof tuberculosis (TB) from high-risk clients toemployees working in housing programadministrative offices.

Keywords: SIC 9531 (Administration of Hous-ing Programs), TB, engineering controls.

Abstract: NIOSH investigators met with staffand management of this city housing programto discuss potential transmission of TB fromhigh-risk clients to employees. NIOSH wasasked to provide advice about procedures andengineering controls to prevent occupationaltransmission of TB. NIOSH representativesdid not collect specific data about the risk ofTB infection incurred from relatively briefvisits to the offices by applicants seekinghousing. However, many of the applicantsappear to fall within high-risk categories foractive TB disease. Therefore, it is reasonableto take measures to reduce the chances of TBtransmission. Recommendations for reducingexposure risk through employee education andearly identification of persons with symptomsof active disease were provided in the closeoutreport.



Purpose: To investigate the potential for tubercu-losis (TB) transmission resulting from autopsiesof persons with TB at time of death.

Keywords: SIC 9199 (General Government NotElsewhere Classified), autopsy, morgue, TB,germicidal ultraviolet (UV) radiation, ventila-tion.

Abstract: NIOSH investigators conducted anevaluation at this medical examiner’s officeregarding the potential for TB transmissionresulting from autopsies conducted on personswho had active multidrug-resistant TB at thetime of their death. Investigators evaluated theventilation systems serving the morgue andoffice areas and observed work practices and useof personal protective equipment during anautopsy. A fog-generating device and ventilationsmoke tubes used to visually assess airflowpatterns demonstrated the potential for airmovement out of the morgue and into surround-ing areas. Thus, researchers concluded that apotential hazard existed for workers exposed toaerosols containing Mycobacterium tuberculosisgenerated during autopsy. The use of high-speedtools and other aerosol generating proceduresthat encounter collections of TB-infected mate-rial presents a potentially high-risk exposuresituation. Recommendations were made in thereport to correct existing ventilation deficiencies,including isolation of the morgue ventilationsystem, use of personal protective equipment,safe use of germicidal UV lamps, and theprovision of separate clean and dirty changeareas for morgue personnel.


Coroner’s Office


13

HETA 96–0019–2666December 1997

Purpose: To investigate airborne particulatesgenerated by a pneumatic reciprocating sawequipped with local exhaust ventilation(LEV).

Keywords: SIC 9221 (Police Protection), tuber-culosis, human immunodeficiency virus,coroner, bloodborne pathogen, noise, cranialsaws.

Abstract: NIOSH investigators conducted ahealth hazard evaluation in this coroner’soffice to evaluate a pneumatic reciprocatingsaw equipped with LEV used for makingcranial openings during forensic autopsies andexaminations. The objective of the NIOSHevaluation was to determine if the alternativereciprocating saw generated less tissue andbone fragment aerosol that could potentiallyenter the breathing zone of the operatingforensic technician. Differences in peakconcentrations of airborne particulates mea-sured during autopsies with and without theaid of LEV, indicate that LEV significantlyreduced the aerosols produced by the recipro-cating saws. No short-term, high concentra-tions of particulates were observed duringautopsies utilizing the LEV system. LEVapplied at the cutting surface of reciprocatingsurgical saws can be an effective tool toreduce the risk of occupational exposure toblood, bone, and tissue aerosol fragmentsduring autopsies. However, the vacuumsystem should be mechanically integrated withthe activation of the reciprocating saw, elimi-nating the possibility of operator error.


HETA 92–282–2297March 1993

Purpose: To investigate medical departmentstaff exposure to Mycobacterium tuberculosis(M. tuberculosis) at a correctional facility.

Keywords: SIC 9223 (Correctional Institutions),prisons, tuberculosis (TB).

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this correctionalinstitution to determine whether staff in theMedical Department were potentially exposedto M. tuberculosis from an inmate diagnosedwith active TB. NIOSH investigators met withrepresentatives of labor and management tocollect information regarding the patient’sillness, isolation, and treatment, and the TBscreening programs provided by the correc-tional institution. The heating, ventilating, andair-conditioning system in the Medical De-partment was evaluated to identify possibledeficiencies that could contribute to thetransmission of M. tuberculosis. The majorityof air in the building was recirculated. Be-cause of this, there was a potential for M.tuberculosis from the Medical Department tobe transmitted throughout that department aswell as the administrative offices. Otherventilation deficiencies that may increase thepotential for M. tuberculosis transmissionincluded insufficient total and outside airsupply, and incorrect pressure relationshipsbetween rooms and adjacent corridors. Rec-ommendations to reduce the potential for M.tuberculosis transmission, including medicalscreening and improved ventilation, wereprovided in the report.


Correctional Facilities


HETA 93-0364May 1993

Purpose: To evaluate the tuberculosis (TB)control policy at this youth detention center.

Keywords: SIC (9223 Correctional Institutions),TB, correctional facility, detention, youth,tuberculin skin test.

Abstract: NIOSH investigators reviewed the TBcontrol policy at this youth detention center.The detention center’s policy required TB skintesting for all employees at time of employ-ment and annually thereafter. Review of themedical department TB records revealed thatthe records were incomplete. Test results andfollow-up procedures were recorded on anumber of different forms located in differentareas. In addition, many of the negative skintests were recorded in the records as “nega-tive,” rather than as the number of millimetersof induration. The only skin test conversiondocumented in the records occurred in 1982.There had been no known active TB casesamong residents or staff at the detentioncenter. Recommendations were made in thereport to develop a written TB control pro-gram in accordance with the Centers forDisease Control and Prevention guidelines,improve record keeping, and enhance TBeducational efforts.


HETA 93-0748January 1996

Purpose: To evaluate the ventilation systemsserving this county jail.

Keywords: SIC (9223 Correctional Institutions),tuberculosis (TB), correctional facility, jail,ventilation.

Abstract: NIOSH investigators conducted aventilation system evaluation to assess thepotential for dissemination of airborne Myco-bacterium tuberculosis (M. tuberculosis) atthis county jail. The ventilation system evalua-tion consisted of a review of mechanicalplans, discussions with persons responsible formaintenance of the heating, ventilation, andair-conditioning (HVAC) systems, and avisual assessment of air flow patterns (usingchemical smoke) in the cell block areas.HVACs of various designs were observedthroughout the jail. Many of the systems orcomponents were inoperable. In some areas,natural ventilation (open windows) and ceilingfans were used to enhance the mechanicalventilation. In the cell block area used toisolate suspected TB infected inmates, theexhaust and supply duct work to the individualcells and associated corridors were discon-nected from the central HVAC system tominimize the recirculation of contaminatedair. However, this also resulted in no outdoorair being delivered to the occupied spaces. Afloor fan was positioned to blow air across theface of the isolation cells, and another waspositioned perpendicular to the first, exhaust-ing entrained air out of an open door. Basedon the location of the guard’s desk, air fromthe cells that was not exhausted was directedat the guard. Recommendations were made tocorrect the ventilation deficiencies and im-prove directional air flow, dilution, and re-moval of contaminated air. Additional recom-mendations were made to improve the overallTB control program (screening of employees,education and training, use of respiratoryprotection, etc.).



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HETA 94–0238–2484February 1995

Purpose: To investigate the potential for tubercu-losis (TB) transmission among law enforcementpersonnel who have contact with prisoners.

Keywords: SIC 9221 (Police Protection), TB,tuberculin skin test (TST), correctional facility,indoor environmental quality, ventilation.

Abstract: NIOSH representatives conducted anenvironmental and medical evaluation at thiscorrectional facility. Confidential medicalinterviews were conducted with five of the sevenemployees who were reported to have newlyreactive TSTs. The on-site occupational healthnurse was interviewed, and medical recordsand the employee TST program were reviewed.The heating, ventilating, and air-conditioning (HVAC) units that served theoffices and cellblocks were evaluated to deter-mine their effectiveness in reducing the airbornetransmission of infectious agents. The medicalevaluation found that six (9%) of the employeeswho had received a TST had a positive response.The available TST data were not sufficient toassess the prevalence of TB infection or theextent of work-related risk of TB among em-ployees. The physical evaluation of the ventila-tion system indicated that it was potentiallyinadequate, and some of the HVAC units serv-ing the office areas had signs of deficient generalmaintenance. NIOSH investigators determinedthat the employees may have had an increasedrisk of occupationally acquired TB infectionbecause they are in contact with prisoners, agroup considered to be at high risk for develop-ing active TB. Recommendations for an em-ployee TB education and surveillance program,and for improving the work environment,especially the ventilation systems, were pre-sented in the full report.

Copies are available from NTIS, individually oron CD-ROM.

HETA 95–0024–2518August 1995

Purpose: To investigate the potential for tuber-culosis (TB) transmission among law enforce-ment personnel who have contact with prison-ers.

Keywords: SIC 9221 (Police Protection), TB,tuberculin skin test (TST), correctional facil-ity, prisoners, indoor environmental qualityventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this correctionalfacility to evaluate the potential for TB trans-mission among personnel who have contactwith prisoners. Confidential medical inter-views were conducted with employees whowere reported to have newly reactive TSTs,and medical records and the employee TSTprogram were reviewed. A walk-throughinspection of the facility was conducted, andventilation measurements were made toevaluate the potential for dissemination ofdroplet nuclei. The environmental evaluationrevealed deficiencies in the amount of outdoorair supplied to the cell block area and in thedelivery of supply air to the cell block andoffice areas. These deficiencies minimize thecontribution of ventilation and directionalairflow in diluting or removing contaminatedair. The available TST data were not sufficientto assess the prevalence of TB infection or theoccupational risk of TB transmission amongemployees. However, employees have contactwith prisoners, a group considered to be athigh risk for developing active TB. Recom-mendations for improving the TST surveillance program and environmental controlswere provided in the report.



HETA 92–0377–2625January 1997

Purpose: To investigate the transmission of TBamong employees working in laboratorieswhere clinical specimens are processed.

Keywords: SIC 8071 (Medical Laboratories),TB, laboratory-acquired infections, skintesting, ventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this medicallaboratory regarding the transmission oftuberculosis among employees working inlaboratories where clinical specimens wereprocessed. Workers handling viable Mycobac-terium tuberculosis (M. tuberculosis) speci-mens may be at increased risk of becominginfected while performing their jobs. Accord-ing to employee recall, 23% of persons em-ployed in the labs converted to a positivetuberculin skin test over an 8-year period.However, limitations of the study made itdifficult to draw any definitive conclusionsregarding the risk of occupational transmis-sion of M. tuberculosis among the employeesat these laboratories. It is imperative that thelaboratory follows current Centers for DiseaseControl and Prevention guidelines for han-dling M. tuberculosis samples. Recommenda-tions were offered in the full report to reducethe risk of occupational transmission of TBand to improve the working environment forthe employees.


HETA 93–0282–2303April 1993

Purpose: To investigate possible exposures toultraviolet (UV) radiation in a hospital micro-biology laboratory.

Keywords: SIC 8071 (Medical Laboratories),tuberculosis (TB), UV radiation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation to evaluate possibleexposures to ultraviolet radiation in a hospitalmicrobiology laboratory. Exposure to UVradiation was from germicidal UV lampspresent in a Class II Type A biological safetycabinet (BSC). Ultraviolet radiation levelsvaried widely, depending on the location ofmeasurement. At eye level directly in front ofthe BSC, irradiance was approximately4.0 microwatts per square centimeter (µW/cm2); this equates to a NIOSH/ACGIH per-missible exposure time of 25 minutes forunprotected workers. The UV irradiance at anadjacent computer terminal (eye level) was 0.8µW/cm2 (permissible exposure time of 120minutes). Exposure to UV radiation wasdetermined to present a potential health hazardfor employees working near the BSC. Recom-mendations to minimize employee exposuresto UV are included in the report.


Laboratory


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HETA 93–0769–2489February 1995

Purpose: To investigate the potential for Myco-bacterium tuberculosis (M. tuberculosis)transmission in this mycobacteriology labora-tory.

Keywords: SIC 8071 (Medical Laboratories),tuberculosis (TB), laboratory-acquired infec-tions, skin testing, ventilation.

Abstract: NIOSH investigators conducted anevaluation to assess the control measures usedto prevent M. tuberculosis transmission in thismycobacteriology laboratory. A walk-throughsurvey of the laboratory and a visualassessment of its heating, ventilating, and airconditioning system was conducted at the timeof the site visit. Additionally, the employeetuberculin skin testing (TST) program wasreviewed, and a microbiologist was observedduring the processing of samples to evaluatework practices and procedures. The visualassessment of the ventilation system andevaluation of the design of the laboratoryrevealed that the potential exists for dissemi-nation of M. tuberculosis to other parts of thelaboratory. The facility did not have a writtenTST surveillance program and, at the time ofthe evaluation, no central file was used fortracking TST results. A respiratory protectionprogram meeting Occupational Safety andHealth Administration requirements had notbeen implemented for the laboratory. Apotential health hazard existed for workerswho may be exposed to aerosols generated inthe laboratory, due to deficiencies in thedesign of the laboratory and operation of theventilation system and the lack of appropriaterespiratory protection. Since the TB laboratoryis not properly sealed, the possibility existedthat M. tuberculosis bacilli could be dissemi-nated to other areas of the laboratory. Recom-mendations were presented in this report to

correct deficiencies identified during theevaluation and to meet the minimum guide-lines recommended by Centers for DiseaseControl and Prevention and National Institutesof Health.


HETA 98–0296November 1998

Purpose: To investigate the tuberculosis (TB)transmission controls in place in amycobacteriology laboratory.

Keywords: SIC 8071 (Medical Laboratories),TB, laboratory-acquired infections, ventila-tion.

Abstract: An evaluation of thismycobacteriology laboratory was conducted toassess the TB controls in place at the facility.Measurements were taken for airflow, airstatic pressure, and particle counts to quantifycontainment parameters. Measurements werealso made of the energy produced by ultravio-let germicidal irradiation (UVGI) lampslocated in the bacteriology laboratory, thebiology safety cabinet, and the BiosafetyLevel 3 containment laboratory. NIOSHinvestigators found that the use of physicalbarriers alone could not prevent the migrationof contaminants from one area to another.NIOSH recommended the use of generalventilation to create pressure differentialsbetween activity zones to minimize opportuni-ties for contaminant escape when doors areopened. Additional recommendations concern-ing the use of UVGI and respiratory protectionare made in the report, along with recommen-dations for preventative maintenance of theventilation system and laboratory hoods.



HETA 92–0320–2357October 1993

Purpose: To investigate control measures usedto prevent tuberculosis (TB) transmission at asocial service facility and homeless center.

Keywords: SIC 8399 (Social Services, NotElsewhere Classified), TB, germicidal ultra-violet (GUV) radiation, skin testing, ventila-tion.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at a social servicesfacility that provides counseling, medical care,and housing assistance for homeless clients.NIOSH was asked to investigate the opera-tional status of a ventilation system and GUVlamps in preventing TB transmission, alongwith assessing the potential for Mycobacte-rium tuberculosis (M. tuberculosis) exposuresfrom the homeless center located in the samebuilding. At this facility, investigators re-viewed the written tuberculin screeningprogram and results of the client and em-ployee tuberculin skin tests (TST). A visualassessment of the ventilation system andairflow patterns was made, and measurementsof the supply and exhaust airflows wereobtained and compared to the design specifi-cations. The majority of the air in the facilityis recirculated and therefore, there is potentialfor airborne M. tuberculosis to be transmittedthroughout the facility. Other deficienciesidentified that may increase the potential forTB transmission included insufficient outsideair supply and inconsistent client screeningtechniques. At the homeless center, a visualassessment of the ventilation system wasperformed and results of the employee tuber-culin screening were reviewed. The onlymechanical ventilation systems are the exhaust

fans, in the bathrooms, gymnasium, andkitchen and the cool-air recirculating systemin the cafeteria. Since the center relies onexhaust fans and natural ventilation for dilu-tion and removal of air contaminants, a poten-tial for TB exposures exists whenever a clientwith active TB attends the center. A potentialhealth hazard existed for workers exposed toclients who have active TB in both the socialservices facility and the homeless center. Thereport, contained recommendations to reducethe potential for TB transmission, includingimproved TST screening and ventilation ateach facility.


HETA 93–0771–2437July 1994

Purpose: To investigate the potential for Myco-bacterium tuberculosis (M. tuberculosis)transmission in a residential care facility.

Keywords: SIC 8361 (Social Services, Residen-tial Care), tuberculosis (TB), human immuno-deficiency virus (HIV)-infection, skin testing,ventilation.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this residential carefacility to evaluate the potential for M. tuber-culosis transmission in the residential facilityduplexes that were to provide housing forhomeless HIV- infected persons. On the basisof a review of the plans of the facility and awalk-through inspection, a room was selectedthat could be used to house individuals withsuspected infectious TB. The room wasrecommended on the basis of its remotelocation within the complex and the ability tooptimize ventilation rates. Further evaluationwas recommended to ensure that short-circuit-ing of the supply and exhaust airflows would

Homeless Shelters


19

not occur. Investigators found that a potentialhealth hazard existed due to deficiencies in theventilation system and the lack of appropriaterespiratory protection. At the time of theinvestigation, no guidelines addressing M.tuberculosis exposures existed in residentialfacilities for HIV-infected individuals; how-ever, many of the guidelines pertaining tohealth care facilities are applicable for thistype of setting. The report contained recom-mendations regarding administrative andengineering controls and the use of appropri-ate respiratory protection to prevent M. tuber-culosis transmission in the facility, as well asduring the transport of potentially infectiousindividuals.


HETA 93–0859August 1995

Purpose: To investigate the potential for expo-sure to tuberculosis (TB) during inspection ofnonhuman primates.

Keywords: SIC 9512 (Land, Mineral, Wildlife,and Forest Conservation), TB, nonhumanprimates, zoonotic pathogens.

Abstract: NIOSH and the Centers for DiseaseControl and Prevention investigators made asite visit to an airport to observe proceduresused during inspection of two shipments ofimported nonhuman primates. NIOSH investi-gators observed and conducted an interviewwith an animal inspector. The investigatorsobserved that the inspector’s actual contactwith the animals was very brief during aroutine inspection. “Contact” was defined asbeing within 5 feet of an animal. The inspec-

tions were done on the airport tarmac. Basedon observations from this evaluation, inspec-tors have the potential for exposures tozoonotic pathogens including Mycobacteriumtuberculosis during inspection of nonhumanprimate shipments. This risk is minimized inthat inspectors are not required to handle theanimals or cages during routine inspection.Considering that inspectors do not have directphysical contact with the animals or cagesduring routine inspection, the most probableroute of exposure for zoonotic pathogensduring inspection would be respiratory expo-sure. On the basis of the brief nature of thework task and the variable nature of the worklocations and environments, engineeringcontrols such as exhaust ventilation would bedifficult to use as a control for respiratoryexposures. Personal protective equipment wasnoted to be a more suitable control alternative.


HETA 95–0031–2601October 1996

Purpose: To investigate the effectiveness of asupplemental high efficiency particulate air(HEPA) filtration system in reducing potentialtuberculosis (TB) transmission.

Keywords: SIC 4119 (Local Passenger Trans-portation, Not Elsewhere Classified), TB,ambulance, emergency medical services,Emergency medical service (EMS), healthcare, HEPA filtration.

Abstract: NIOSH investigators conducted ahealth hazard evaluation at this medical centerto evaluate a supplemental HEPA filtrationsystem installed in a new ambulance. NIOSHinvestigators conducted a field evaluation ofparticle clearance in an ambulance equippedwith a supplemental HEPA filtration system.A similar ambulance without the HEPA

Other Facilities


filtration system was also evaluated for com-parison. The results indicated that the ambu-lance with the supplemental HEPA filtrationsystem cleared particles faster than the ambu-lance without the supplemental system, whentested under similar conditions. This evalua-tion also showed that particle clearance couldbe improved by the use of the rear vent fan(when positioned on the “high” setting) inconjunction with the provision of outside airthrough the vehicle’s main heating, ventilat-ing, and air-conditioning systems. For vehiclesthat do not have supplemental HEPA filtrationsystems, using the vent fan and providingoutside air through the vehicle’s main HVACsystem improves aerosol clearance and thusreduces the potential risk of TB transmission.Recommendations concerning the use ofrespiratory protection by workers duringtransport of known or suspected infectious TBpatients, and for the performance of regularpreventive maintenance and leak testing of theHEPA unit were included in the report.


HETA 95–0328–2630March 1997

Purpose: To investigate the ventilation systemat this textile sewing plant.

Keywords: SIC 2361 (Girls’, Children’s, andInfants’ Dresses, Blouses, and Shirts), tuber-culosis (TB), sewing, ventilation, tracer gas,sulfur hexafluoride.

Abstract: NIOSH researchers conducted anevaluation of this sewing plant to evaluate theventilation system after one employee wasdiagnosed with TB and a large number of otherstested positive on tuberculin skin tests. NIOSHinvestigators performed an initial evaluation tomeasure airflow rates and assess air movementwithin the plant. An in-depth ventilation assess-ment was later made to document conditions thatlikely occurred during the period that the em-ployee with TB was infectious. This involved atracer gas evaluation to quantify the extent andspeed of contaminant dispersion and contami-nant removal rate. When the tracer gas wasreleased in the middle of the plant, it was de-tected at the furthest points in the productionarea (approximately 100 feet away) within 11minutes. The tracer gas was also detected in theengineering and main office areas, the cafeteria,and the conference room. The NIOSH evalua-tion determined that ventilation conditions werefavorable for TB transmission based on a low airchange rate and excellent air mixing within theplant. Thus, TB bacteria would have spreadquickly and uniformly throughout the plant andremain suspended for hours before being re-moved from the air. Other factors that may haveinfluenced TB transmission include prolongedinfectiousness of the individual, virulence of theorganism, and TB exposure outside the work-place. Recommendations for improving generalventilation were made in the report.



21

HETA 98–0027–2709March 1998

Purpose: To investigate potential occupationalexposures to Mycobacterium tuberculosis(M. tuberculosis) at a biomedical wastedisposal facility.

Keywords: SIC 4953 (Refuse Systems), tuber-culosis (TB), biomedical waste.

Abstract: NIOSH investigators conducted ahealth hazard evaluation to evaluate potentialoccupational exposures to M. tuberculosis atthis medical waste treatment facility. Therequest concerned exposures to M. tubercu-losis from the processing of infectious wastedue to a recent outbreak of TB amongemployees at the facility. NIOSH investiga-tors conducted a site visit to (1) observework practices, (2) collect information aboutthe operation and maintenance of the pro-cess equipment, and (3) discuss companypolicies regarding the use of personal pro-tective equipment, training programs, andaccident/injury and spill response. NIOSHidentified several factors in the facility thatcould contribute to employee exposures topathogens potentially present in the medicalwaste. These included the use of a process thatcreates the potential for aerosolization of theproducts contained in the waste prior todeactivation; deficiencies in the design of thefacility; the policies in place at the facility; thedesign and operation of the equipment used atthe facility (including personal protectiveequipment); and misunderstandings amongemployees about operations, personal protec-tive equipment, medical issues, and policiesand procedures. Recommendations to helpprevent exposures to M. tuberculosis andbloodborne pathogens are provided in thereport.


Documents

Health Hazard Evaluations: TuberculosisHealth Hazard Evaluations: Tuberculosis 1990 to 1999 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Centers for Disease Control