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HETA 95-0311-2593Martin’s Carstar, Inc.Lakewood, Colorado

Charles McCammon

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports



This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.


applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE reports are available at http://www.cdc.gov/niosh/hhe/reports

http://www.cdc.gov/niosh/hhe/reports



ii

PREFACEThe Hazard Evaluations and Technical Assistance Branch of NIOSH conducts field investigations of possiblehealth hazards in the workplace. These investigations are conducted under the authority of Section 20(a)(6)of the Occupational Safety and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes the Secretary ofHealth and Human Services, following a written request from any employer or authorized representative ofemployees, to determine whether any substance normally found in the place of employment has potentiallytoxic effects in such concentrations as used or found.

The Hazard Evaluations and Technical Assistance Branch also provides, upon request, technical andconsultative assistance to Federal, State, and local agencies; labor; industry; and other groups or individualsto control occupational health hazards and to prevent related trauma and disease. Mention of company namesor products does not constitute endorsement by the National Institute for Occupational Safety and Health.

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORTThis report was prepared by Charles McCammon, of the NIOSH Denver Field Office, Hazard Evaluationsand Technical Assistance Branch, Division of Surveillance, Hazard Evaluations and Field Studies(DSHEFS). Field assistance was provided by Bambi L. Sorensen and Robb Menzies. Desktop publishingby Pat Lovell.

Copies of this report have been sent to employee and management representatives at Martin’s and the OSHARegional Office. This report is not copyrighted and may be freely reproduced. Single copies of this reportwill be available for a period of three years from the date of this report. To expedite your request, includea self-addressed mailing label along with your written request to:

NIOSH Publications Office4676 Columbia ParkwayCincinnati, Ohio 45226

800-356-4674

After this time, copies may be purchased from the National Technical Information Service (NTIS) at5825 Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may beobtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall beposted by the employer in a prominent place accessible to the employees for aperiod of 30 calendar days.

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Health Hazard Evaluation Report 95-0311-2593Martin’s Carstar, Inc.Lakewood, Colorado

August 1996

Charles McCammon

SUMMARYOn June 24, 1995, the National Institute for Occupational Safety and Health (NIOSH) received a request from thePresident of Martin’s Carstar in Lakewood, Colorado, for help in assessing worker exposure to isocyanates duringspray painting of automobiles. Martin’s Carstar is an autobody repair shop whose other concerns for workerexposure included solvents, total dusts, noise, carbon monoxide (CO), and metals. An initial survey was conductedin August 1995 and an interim report was issued in December 1995. To assess effects of seasonal variation, asecond survey was conducted on March 8, 1996. This report summarizes the exposures from both surveys.

Activities in the repair shop include frame straightening, panel repair/replacement, body filling, and final paintingand detailing. Martin’s uses the BASF Corp. Glasurit isocyanate catalyzed paints. In general, the paints arecomposed of a base coat, a reducer, and a hardener. The percentage and make-up of each component variesdepending on the type of paint, i.e., a base coat, a color coat, or a top (clear) coat. The paints containhexamethylene-1,6-diisocyanate (HDI) polymer and very small amounts of the monomer (<0.006%). Some of thehardeners also contain isophorone diisocyanate (IPDI) polymer and monomer. All of the various componentscontain solvents, especially the reducers which are all solvents.

Personal breathing zone (PBZ) and area airborne levels of isocyanate (HDI only) monomer and oligomers, varioussolvents (including n-butyl acetate, toluene, xylene, and ethyl acetate), total dust (paint overspray), metals (fromwelding), carbon monoxide, and noise levels were measured. All of the oligomer and most of the monomersamples collected in August 1995 were below the analytical limit of detection of 2 micrograms (µg) per sample.One area sample collected within the spray booth found a trace amount of the oligomer. One personal samplecollected on the head painter at the end of the day when he was applying clear coat paint measured 99 microgramsper cubic meter, (µg/m3) which is above the NIOSH REL of 35 µg/m3 for an 8-hr TWA but below the 140 µg/m3

ceiling REL. The head painter’s TWA for the day was 29 µg/m3. The samples from February 1996 showed allmonomer exposures as below the analytical limit of detection; most oligomer samples had detectable results.These ranged from 83 to 482 µg/m3.

Air samples for solvents (n-butyl acetate, toluene, xylene, or ethyl acetate) did not exceed their respective REL orPEL, nor did the mixture summation exceed any evaluation criteria. Generally, the levels of organics measuredin February were higher than those in August. Area total dust samples ranged from 4 to 36 mg/m3. Most of thesesamples were collected in the spray booth. PBZ total dust samples ranged from non-detectable (0.02 mg/filter) to7.5 mg/m3. All PBZ samples were below the PEL of 15 mg/m3. Generally, the results from August were higherthan those collected in February. The CO levels averaged 27 ppm for the 8-hr sampling period. The peak CO

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level was 450 ppm and the highest 15-minute average was 105 ppm. The high peaks were associated with movingvehicles in and out of the shop. A personal noise monitor was placed on a body repair worker. The average noiselevel (using the OSHA criteria) was 79 dBA, resulting in a 21% dose of the maximum allowable noise exposure(projected to 28% for a full 8 hours). The maximum peak level measured was 115 dBA. Using a 3 dB exchangerate (NIOSH criteria), the dose percent was 78% with a projected 8-hr dose of 106%. One PBZ welding samplewas collected. Exposures to all metals were well below the respective evaluation criteria.

A potential health hazard exists from exposure to peak levels of carbon monoxide during the cold weathermonths. Levels of isocyanates, solvents, total dust, and noise were below respective evaluation criteria.Area levels of total dust in the spray booths were above the OSHA PEL but workers were wearing eitherdust/mist/organics cartridge air-purifying or air-supplied respirators. The use of air-purifying respiratorswas deemed sufficient for the exposures documented. Recommendations are presented for control ofexposures to CO and to help reduce other exposures.

Keywords: SIC 7531(automotive body shops), isocyanates, solvents, total dust, carbon monoxide, noise,respirators

TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Acknowledgments and Availability of Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Isocyanates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Total Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Organics (solvents) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Carbon Monoxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Evaluation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Carbon Monoxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Organic Solvents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Isocyanates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Diisocyanate-induced sensitization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Prevention and treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Noise/Hearing Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Page 2 Health Hazard Evaluation Report No. 95-0311

INTRODUCTIONOn June 24, 1995, the National Institute forOccupational Safety and Health (NIOSH) received arequest from the President of Martin’s Carstar inLakewood, Colorado, for help in assessing workerexposure to isocyanates during spray painting ofautomobiles. Martin’s Carstar is an autobody repairshop whose other concerns for worker exposureincluded solvents, total dusts, noise, carbonmonoxide (CO), and metals. An initial survey wasconducted in August 1995 and an interim reportcompleted in December 1995. To asess seasonalvariations, a second survey was conducted on March8, 1996. This report summarizes both investigations.

BACKGROUNDThe auto body repair work includes framestraightening, panel repair/replacement, body filling,and final painting and detailing. Repair is conductedin an open shop with body work performed in thenorth end, detail and cleaning in the center, andpainting in the south end. Most top coat spraying isconducted in a paint spray booth located near thesouth end of the shop. Adjacent to the spray booth isa paint mixing room where the paint components arestored and mixed. The paint mixing room isventilated with a separate supply duct located nearthe door and an exhaust at the far (north) end of theroom. The side-draft spray booth has a separate one-pass exhaust system. The booth also has the capacityto be heated to accelerate paint drying.

When painting, multiple thin layers of the differentpaints are applied. When base metal is exposed,these areas are first covered with a primer. Once thevehicle is ready for final painting, several base coatsare applied, the paint is allowed to sit a short while(10-20 minutes), then the color paint is applied,again in several thin coats. Lastly, the clear top coatis sprayed on until a uniform gloss is achieved. Thevehicle is then allowed to sit overnight or in a heatedbooth for 1-2 hours to allow the paint to dry.

New, high volume, low pressure (HVLP) spray gunsare used to reduce the amount of paint over-spray.However, most of the painters still used theconventional spray gun to some degree, especiallywhen applying the clear coats of paint. While mostpainting was done in the spray booth, sometimes,due to the number of cars being painted and thelimitations on drying times, many of the variousprimer, base, and color coats were applied outsidethe spray booth. Most of the clear coats were appliedin the spray booth to insure a dust-free finish coat.

METHODS

IsocyanatesAir samples for isocyanates were collected in 20-mLof an absorbing solution in a midget impinger at aflow rate of 1.0 liter per minute using MSA Model Gsampling pumps. The absorbing solution containeda reactive chemical dissolved in dimethyl sulfoxide.The samples were analyzed by high performanceliquid chromatography (HPLC) according to NIOSHAnalytical Method #5522.1 Since it is difficult toattach midget impingers in the breathing zone ofworkers, particularly since they had to bend over andmove around, the impingers were attached to thesampling pumps on the worker’s belt. Bulk samplesof the various paint components were analyzed byHPLC to determine the amount of free isocyanatemonomer present.

Isocyanate wipe samples were collected on worksurfaces and worker’s hands using colorimetricSWYPETM skin and surface wipe tests developed byColorimetric Laboratories, Inc (CLI, Des Plains,Illinois). Perma-TecTM glove breakthroughindicators also developed by CLI were used to detectany isocyanates penetrating through gloves worn byworkers.

Total Dust Air samples for total dust were collected on 35-

Health Hazard Evaluation Report No. 95-0311 Page 3

millimeter pre-weighed glass fiber filters housed inplastic cassettes. Air was drawn through the filters ata flow rate of 2 liters per minute using batteryoperated Gilian Model HFS 513A high flow pumps.The filters were analyzed gravimetrically accordingto NIOSH Analytical Method # 0500.1

Organics (solvents)Air samples for organic chemicals (n-butyl acetate,xylene, toluene, and ethyl acetate) were collected onstandard 150-milligram charcoal tubes at 200milliliters per minute using battery operated Gilianmodel LFS 113D-C. The samples were analyzed bygas chromatography according to NIOSH AnalyticalMethods #1450 and 1501.1 One charcoal tubesample from each location was screened by gaschromatography/mass spectrometry (GC/MS) todetermine what specific hydrocarbons were presentin the air and approximate levels of each.

Carbon MonoxideCarbon monoxide (CO) levels were measured witha Draeger Model 190 Datalogger. This instrumentuses an electochemical sensor for CO. It wascalibrated on the day of use and zeroed in the field.

NoisePersonal noise measurements were taken with QuestTechnologies Model M-27 Noise LoggingDosimeters. The unit stores and interprets data for avariety of different thresholds and exchange ratesallowing comparison to different recommendedevaluation criteria.

EVALUATION CRITERIAAs a guide to the evaluation of the hazards posed by

workplace exposures, NIOSH field staff employenvironmental evaluation criteria for the assessmentof a number of chemical and physical agents. Thesecriteria are intended to suggest levels of exposure towhich most workers may be exposed up to 10 hoursper day, 40 hours per week for a working lifetimewithout experiencing adverse health effects. It is,however, important to note that not all workers willbe protected from adverse health effects even thoughtheir exposures are maintained below these levels. Asmall percentage may experience adverse healtheffects because of individual susceptibility, apre-existing medical condition, and/or ahypersensitivity (allergy). In addition, somehazardous substances may act in combination withother workplace exposures, the general environment,or with medications or personal habits of the workerto produce health effects even if the occupationalexposures are controlled at the level set by thecriterion. These combined effects are often notconsidered in the evaluation criteria. Also, somesubstances are absorbed by direct contact with theskin and mucous membranes, and thus potentiallyincrease the overall exposure. Finally, evaluationcriteria may change over the years as newinformation on the toxic effects of an agent becomeavailable.

The primary sources of environmental evaluationcriteria for the workplace are: (1) NIOSHRecommended Exposure Limits (RELs)1, (2) theAmerican Conference of Governmental IndustrialHygienists' (ACGIH) Threshold Limit Values(TLVs™)2, and (3) the U.S. Department of Labor,OSHA Permissible Exposure Limits (PELs)3.In July 1992, the 11th Circuit Court of Appealsvacated the 1989 OSHA PEL Air ContaminantsStandard. OSHA is currently enforcing the 1971standards which are listed as transitional values inthe current Code of Federal Regulations; however,some states operating their own OSHA approved jobsafety and health programs continue to enforce the1989 limits. NIOSH encourages employers tofollow the 1989 OSHA limits, the NIOSH RELs, theACGIH TLVs, or whichever are the more protectivecriterion. The OSHA PELs reflect the feasibility ofcontrolling exposures in various industries where the


agents are used, whereas NIOSH RELs are basedprimarily on concerns relating to the prevention ofoccupational disease. It should be noted whenreviewing this report that employers are legallyrequired to meet those levels specified by an OSHAstandard and that the OSHA PELs included in thisreport reflect the 1971 values.

A time-weighted average (TWA) exposure refers tothe average airborne concentration of a substanceduring a normal 8-to-10-hour workday. Somesubstances have recommended short-term exposurelimits (STEL) or ceiling values which are intended tosupplement the TWA where there are recognizedtoxic effects from higher exposures over theshort-term. A brief discussion of the toxicity andevaluation criteria for the substances monitoredfollows: Carbon Monoxide

Carbon monoxide (CO) is a colorless, odorless,tasteless gas produced by incomplete burning ofcarbon-containing materials; e.g., natural gas. Theinitial symptoms of CO poisoning may includeheadache, dizziness, drowsiness, and nausea. Theseinitial symptoms may advance to vomiting, loss ofconsciousness, and collapse if prolonged or highexposures are encountered. Coma or death mayoccur if high exposures continue.2-7

The NIOSH REL for CO is 35 ppm for an 8-hourTWA exposure, with a ceiling limit of 200 ppmwhich should not be exceeded.8,9 The NIOSH RELof 35 ppm is designed to protect workers from healtheffects associated with COHb levels in excess of5%.2 The ACGIH recommends an 8-hour TWATLV of 50 ppm, with a ceiling level of 400 ppm.Currently, the ACGIH has published a notice of anintent to change the TLV to 25 ppm as an 8-hourTWA.10 The OSHA PEL for CO is 50 ppm for an 8-hour TWA exposure. In addition to these standards,the National Research Council has developed a COexposure standard of 15 ppm, based on a 24 hoursper day, 90-day TWA exposure.11

Organic Solvents

Exposure to organic solvents can occur throughinhalation of the vapors, skin contact with the liquid,or ingestion. As many organic solvents haverelatively high vapor pressures and readily evaporate,inhalation of vapors is considered a primary route ofexposure. Overexposure to many organic solventscan result in irritation, central nervous systemdepression, headache, nausea, and possible effects onthe liver, kidney, or other organs.12-14 Manyindustrial solvents are primary irritants, and cancause defatting of the skin and dermatitis. Solventsare among the leading causes of occupational skindisease.14 Biological effects of exposure can rangefrom practically non-toxic (e.g., some freons) tohighly toxic (e.g., carbon tetrachloride) orcarcinogenic (e.g., benzene).3 The ability to detectthe presence of a solvent by the sense of smell willvary widely depending on the specific substance, andindividual sensitivity. Substances are considered tohave good warning properties if an average personwith normal sensory perception can detect thepresence of the chemical at a level below therecommended exposure limit. The following tablesummarizes the principle health effects associatedwith these solvents and the NIOSH RELs and odordetection thresholds for these compounds.

Chemical NIOSH REL Odor Threshold& Description16

PrincipleHealth

Effects5,15-17

ethyl acetate 400 ppm 1 ppmsweet/fruity

centralnervoussystemdepression,dizziness, eyeirritation


methyl-ethylketone

(2-butanone)

200 TWA300 ppm

STEL

17 ppmsweet, sharp

headache,dizziness,numbness ofextremities,dermal andeye irritation

toluene100 TWA150 ppm

STEL

1.6 ppmsour, burnt

eye/respiratoryirritation,fatigue,headache,narcoticeffects

xylene100 TWA150 ppm

STEL

20 ppmsweet

eye/respiratoryirritation,narcosis,headache,dermal effects

acetone 250 ppmTWA

62 ppmsweet, fruity

eye irritation,nausea,headache,centralnervoussystemdepression

N-butylacetate

200 STEL150 ppm

TWA

7 ppmsweet, fruity

eye/respiratoryirritation,narcosis

Note:TWA = time-weighted average concentration for up to 10

hours/dayC = ceiling limit not to be exceededSTEL = short-term exposure limit - 15 minute average

Note that many solvents have similar toxic effects.When there are exposures to two or more substancesthat act upon the same organ system, their combinedeffect is evaluated. Unless there is scientificevidence to the contrary, the effects are considered tobe additive (as opposed to potentiating, synergistic,or antagonistic), and are calculated as follows:

Combined REL = C1 + C2 +...CnREL1 REL2 RELn

Where: C = measured atmospheric concentrationREL= corresponding recommended exposure limit

If the sum of the above fractions exceeds 1.0, thecombined REL is considered to be exceeded.

Isocyanates The unique feature common to all diisocyanates is

that they consist of two -N=C=O (isocyanate)functional groups attached to an aromatic oraliphatic parent compound. Because of the highlyunsaturated nature of the isocyanate functionalgroup, the diisocyanates readily react withcompounds containing active hydrogen atoms(nucleophiles). Thus, the diisocyanates readily reactwith water (humidity), alcohols, amines, etc.; thediisocyanates also react with themselves to formeither dimers or trimers. When a diisocyanatespecies reacts with a primary, secondary, or tertiaryalcohol, a carbamate (-NHCOO-) group is formedwhich is commonly referred to as a urethane.Reactions involving a diisocyanate species and apolyol result in the formation of cross-linkedpolymers; i.e., polyurethanes. Hence, they arewidely used in surface coatings, polyurethane foams,adhesives, resins, elastomers, binders, sealants, etc.Diisocyanates are usually referred to by theirspecific acronym; e.g., TDI for 2,4- and 2,6-toluenediisocyanate, HDI for 1,6-hexamethylenediisocyanate, MDI for 4,4'-diphenylmethanediisocyanate, NDI for 1,5-naphthalene diisocyanate,etc. Commercial-grade TDI is an 80:20 mixture ofthe 2,4- and 2,6- isomers of TDI, respectively.

In general, the type of exposures encountered duringthe use of diisocyanates in the workplace are relatedto the vapor pressures of the individual compounds.The lower molecular weight diisocyanates tend tovolatilize at room temperature, creating a vaporinhalation hazard. Conversely, the higher molecularweight diisocyanates do not readily volatilize atambient temperatures, but are still an inhalationhazard if aerosolized or heated in the workenvironment. The latter is very important since mostreactions involving diisocyanates are exothermic innature, thus providing the heat for volatilization. Inan attempt to reduce the vapor hazards associatedwith the lower molecular weight diisocyanates,prepolymer and oligomer forms of these monomerswere developed, and have replaced the monomers inmany product formulations. An example is biuret ofHDI, which actually consists of three molecules ofHDI monomer joined together to form a highermolecular weight oligomer with similarcharacteristics to those found in HDI monomer.


Also, many product formulations that contain MDIactually contain a combination of MDI monomerand MDI oligomer (polymethylene polyphenylisocyanate). Experience with both the monomericand oligomeric forms of diisocyanates has shownthat the occurrence of health effects is dependent onexposure, not molecular weight.

Exposure to the diisocyanates produces irritation tothe skin, mucous membranes, eyes, and respiratorytract. High concentrations may result in chemicalbronchitis, chest tightness, nocturnal wakening,pulmonary edema, and death.18,21 The most commonadverse health outcome associated with diisocyanateexposure is increased airway obstruction (asthma),and to a lesser extent dermal sensitization andhypersensitivity pneumonitis.19-21

Diisocyanate-induced sensitization

Probably the most debilitating health effects fromworkplace exposure to diisocyanates are respiratoryand dermal sensitization. Exposures can lead tosensitization depending on the type of exposure, theexposure concentration, the route of exposure, andindividual susceptibility. Dermal sensitization canresult in such symptoms as rash, itching, hives, andswelling of the extremities.18,21 Respiratorysensitization from exposure to diisocyanates resultsin the typical symptoms of asthma. Estimates of theprevalence of diisocyanate-induced asthma inexposed worker populations vary considerably; from5% to 10% in diisocyanate production facilities,22,23

to 25% in polyurethane production plants,22,24 and30% in polyurethane seatcover operations.25

A worker suspected of having diisocyanate-inducedsensitization will present with symptoms oftraditional acute airway obstruction; e.g., coughing,wheezing, shortness of breath, tightness in the chest,nocturnal awakening, etc.18,20 Upon first exposure todiisocyanates, the worker may develop an asthmaticreaction immediately or several hours after exposure,after the first months of exposure, or after several

years of exposure.18,20,23,26,27 Some evidence existswhich suggests that the onset of sensitization occursafter a mean exposure interval of 2 years.28 Aftersensitization, any exposure, even to levels below anyoccupational exposure limit or standard, can producean asthmatic response which may be lifethreatening. This asthmatic reaction may occurminutes after exposure (immediate), several hoursafter exposure (late), or a combination of bothimmediate and late components after exposure(dual).20,26 The late asthmatic reaction is the mostcommon, occurring in approximately 40% ofdiisocyanate-sensitized workers.29 Recurrentnocturnal asthma has been described in workerssensitized to TDI and MDI.30,31 An improvement insymptoms may be observed during periods awayfrom the work environment (weekends,vacations).18,20,26

The percentage of sensitized workers with persistentsymptoms of asthma after years of no exposure maybe 50% or higher. Studies have shown that workerswith persistent asthma have a significantly longerduration of symptoms prior to diagnosis, largerdecrements in pulmonary function, and a severedegree of nonspecific bronchial hyperactivity atdiagnosis.26 These data suggest that prognosis isimproved with early diagnosis of diisocyanate-induced respiratory sensitization and early removalfrom diisocyanate exposure. This emphasizes theneed to minimize workplace exposureconcentrations, and for active medical surveillanceof all workers potentially exposed to diisocyanates.

Prevention and treatment

Whenever there is a potential for a hazardousexposure to diisocyanates, traditional industrialhygiene practice dictates that the followinghierarchy of controls, in decreasing order ofdesirability and effectiveness, be implemented toprotect worker health:

1. Elimination of the toxic substance from theworkplace.

2. Substitution of the toxic substance with a lesstoxic substance.


3. Installation of engineering controls designed toreduce exposure.

4. Use of administrative controls to reduce exposure.

5. Use of personal protective equipment to reduceexposure.

In many instances, it is not possible to eliminate orsubstitute a diisocyanate from a production processwithout altering the integrity of the desired product.Thus, most strategies for reducing diisocyanateexposure center on the use of engineering controlsand personal protective equipment. Local exhaustventilation and/or process isolation are commonlyused controls for diisocyanate exposure reduction.Personal protective equipment should only be usedwhen engineering controls are not feasible, in theinterim when engineering controls are being installedor repaired, or when engineering controls have notsufficiently reduced exposures. NIOSHrecommends that whenever there is a potential forexposure to diisocyanates, including concentrationsbelow the NIOSH recommended exposure level, thatthe employer provide the worker with supplied-airrespiratory protection.18 Air-purifying respirators arenot approved for diisocyanates owing primarily tothe fact that diisocyanates have poor odor warningproperties. However, several studies havedemonstrated that air-purifying respirators withcombined dust/mist and organic cartridgeseffectively trap TDI, HDI, and MDI.32-34 Personalprotective equipment should also be used to preventskin and eye contact with diisocyanates.

OSHA currently has standards for only two of thediisocyanates, TDI and MDI. OSHA recommends aceiling limit of 0.02 parts per million (ppm) [140micrograms per cubic meter, ug/m3] for both TDIand MDI. For MDI, NIOSH recommends a TWA of0.005 ppm (35 ug/m3) and a 10-minute ceiling of0.02 ppm [200 ug/m3]. NIOSH considers TDI acarcinogen and recommends exposure be limited tothe lowest feasible concentration.

For HDI, NIOSH recommends a TWA of 0.005 ppm[35 ug/m3] and a 10-minute ceiling limit of 0.02 ppm

[140 ug/m3]. For isophorone diisocyanate (IPDI),NIOSH recommends a TWA of 0.005 ppm[45 ug/m3] and a ceiling limit of 0.02 ppm[180 ug/m3] with a skin designation. This means thatskin absoption is considered the primary route ofexposure and skin contact should be avoided.

Neither NIOSH nor OSHA have recommendedexposure limits for the polymeric isocyanate groups(oligomers). The United Kingdom Health andSafety Commission set a standard in 1982 for totalisocyanate group per cubic meter of air. Thisstandard is 20 ug of isocyanate group/m3 for a TWAand 70 ug/m3 for a 10-minute ceiling. 35 MilesLaboratories recommends in their MSDS for theGlasurit HDI-based paints that a limit of 500 ug/m3

be followed for the polymeric isocyanates.

Noise/Hearing LossNoise-induced loss of hearing is an irreversible,sensorineural condition that progresses withexposure. Although hearing ability declines with age(presbycusis) in all populations, exposure to noiseproduces hearing loss greater than that resulting fromthe natural aging process. This noise-induced loss iscaused by damage to nerve cells of the innerear (cochlea) and, unlike some conductive hearingdisorders, cannot be treated medically.36 While lossof hearing may result from a single exposure to avery brief impulse noise or explosion, such traumaticlosses are rare. In most cases, noise-induced hearingloss is insidious. Typically, it begins to develop at4000 or 6000 Hz (the hearing range is 20 Hz to20000 Hz) and spreads to lower and higherfrequencies. Often, material impairment hasoccurred before the condition is clearly recognized.Such impairment is usually severe enough topermanently affect a person's ability to hear andunderstand speech under everyday conditions.Although the primary frequencies of human speechrange from 200 Hz to 2000 Hz, research has shownthat the consonant sounds, which enable people todistinguish words such as "fish" from "fist," havestill higher frequency components.37

The A-weighted decibel [dB(A)] is the preferred unit


for measuring sound levels to assess worker noiseexposures. The decibel unit is dimensionless, andrepresents the logarithmic relationship of themeasured sound pressure level to an arbitraryreference sound pressure (20 micropascals, thenormal threshold of human hearing at a frequency of1000 Hz). Decibel units are used because of the verylarge range of sound pressure levels which areaudible to the human ear. The dB(A) scale isweighted to approximate the sensory response of thehuman ear to sound frequencies. Because the dB(A)scale is logarithmic, increases of 3 dBA, 10 dBA,and 20 dBA represent a doubling, tenfold increase,and 100-fold increase of sound energy, respectively.It should be noted that noise exposures expressed indecibels cannot be averaged by taking the simplearithmetic mean.

The OSHA standard for occupational exposure tonoise (29 CFR 1910.95)38 specifies a maximum PELof 90 dB(A)-slow response for a duration ofeight hours per day. The regulation, in calculatingthe PEL, uses a 5 dB time/intensity tradingrelationship, or exchange rate. This means that inorder for a person to be exposed to noise levels of95 dB(A), the amount of time allowed at thisexposure level must be cut in half to be withinOSHA's PEL. Conversely, a person exposed to85 dB(A) is allowed twice as much time at this level(16 hours) and is within his daily PEL. NIOSH, inits Criteria for a Recommended Standard,39 proposesan exposure limit of 85 dB(A) for 8 hours, 5 dB lessthan the OSHA standard. In 1994, the ACGIHchanged its TLV to a more protective 85 dB(A) foran 8-hour exposure, with the stipulation that a 3 dBexchange rate be used to calculate time-varyingnoise exposures.10 Thus, a worker can be exposed to85 dB(A) for 8 hours, but to only 88 dB(A) for4 hours or 91 dB(A) for 2 hours. In 1995, NIOSHalso recommended a 3 dB exchange rate.

Time-weighted average noise limits as a function ofexposure duration are shown as follows:

Sound Level dB(A)

Duration of Exposure(hrs/day)

ACGIH NIOSH OSHA

16 82 82 858 85 85 904 88 88 952 91 91 100 1 94 94 105

1/2 97 97 110 1/4 100 100 115*1/8 103

103 ---

*** *** *** No exposure to continuous or intermittent noise in excess of 115 dB(A).

** Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level.

*** No exposure to continuous, intermittent, or impact noise in excess of a peak C-weighted level of 140 dB.

The duration and sound level intensities can becombined in order to calculate a worker's daily noisedose according to the formula:

Dose = 100 X (C1/T1 + C2/T2 + ... + Cn/Tn ),

where Cn indicates the total time of exposure at aspecific noise level and Tn indicates the referenceduration for that level as given in the above table.During any 24-hour period, a worker is allowed up to100% of his daily noise dose. Doses greater than100% are in excess of the OSHA PEL.

The OSHA regulation has an additional action level(AL) of 85 dB(A) which stipulates that an employershall administer a continuing, effective hearingconservation program when the TWA value exceedsthe AL. The program must include monitoring,employee notification, observation, an audiometrictesting program, hearing protectors, trainingprograms, and recordkeeping requirements. All of


these stipulations are included in 29 CFR 1910.95,paragraphs (c) through (o).

The OSHA noise standard also states that whenworkers are exposed to noise levels in excess of theOSHA PEL of 90 dB(A), feasible engineering oradministrative controls shall be implemented toreduce the workers' exposure levels. Also, acontinuing, effective hearing conservation programshall be implemented.

RESULTSA summary of the isocyanate results from August,1995 are presented in Table 1. All of the oligomerand most of the monomer samples were below theanalytical limit of detection of 1 µg/sample. The lessthan values (<) in the table represent the lowestdetectable concentration for that sample based on thesample volume and the detection limit. Only a traceamount of HDI monomer was detected in sample #MCI-10, which was an area sample within the spraybooth. Sample #MCI-12 was a PBZ samplecollected on the head painter at the end of the daywhen he was applying clear coat paint. This samplewas 99 µg/m3 which is above the NIOSH REL of35 µg/m3 for an 8-hr TWA but below the 140 µg/m3

ceiling REL. If the head painter’s full-shift exposureis summed and time-weighted (samples #MCI-01,03, 05, 06, and 12), his TWA was 29 µg/m3, whichis below the NIOSH REL.

The sample results for isocyanates from February1996 are summarized in Table 1a. All the monomerexposures are below the analytical limit of detectionof 2 µg/sample, but most of the oligomer sampleshad detectable results. These ranged from 83 to482 µg/m3.

Air samples for organics are summarized in Tables2 (August 1995) and 2a (February 1996). None ofthe individual chemical levels (n-butyl acetate,toluene, xylene, or ethyl acetate) exceeded theirindividual REL or PEL. Furthermore, the mixturesummation of all organics (the best indicator for totalorganic exposure), for all samples during bothsampling times was not in excess of any evaluationcriteria. Generally, the levels of organics measuredin February were higher than those in August.

Sample results for total dust are summarized inTables 3 (August) and 3a (February). In both cases,area samples in the booth exceeded the PEL of15 mg/m3. None of the PBZ samples exceeded thePEL. Generally, the results from August werehigher than those collected in February.

The one datalogger monitor output for CO is shownin Figure 1. The CO levels averaged 27 ppm for the8-hr sampling period. The peak CO level was450 ppm and the highest 15-minute average was105 ppm. The high peaks were associated withmoving vehicles in and out of the shop.

A personal noise monitor was placed on a bodyrepair worker for 5 hours and 49 minutes. Theaverage noise level (using the OSHA criteria) was79 dBA, resulting in a 21% dose of the maximumallowable noise exposure (projected to 28% for a full8 hours). The maximum peak levels measured was115 dBA. Using a 3dB exchange rate (NIOSHcriteria), the dose percent was 78% with a projected8-hr dose of 106%.

One welding sample was collected and issummarized in Table 4. Exposures to all metalswere well below the respective evaluation criteria.


DISCUSSIONThe isocyanate results generally demonstrate lowexposures to HDI monomer and oligomers. For bothsampling periods, only one sample was in excess ofthe NIOSH REL of 35 µg/m3 yet it was below themore applicable ceiling REL of 140 µg/m3. Thissample was collected in the warm weather months.The oligomer samples were higher during the wintermonths but were still below what is recommendedby the paint manufacturer (500 µg/m3). Theisocyanates samples indicate the potential for someexposure exists, but not at levels in excess of existingevaluation criteria.

Exposures to solvents were generally higher in thewinter than in the summer. The highest exposureswere around 50% (40-56%) of the allowableexposure for solvent mixtures. The highestexposures were consistently to n-butyl acetate andtoluene. Use of protective gloves to reduce skinexposure (and absorption) of solvents wasinconsistent. Gloves were mostly used when mixingpaint and spray painting but were not always usedduring spray gun cleaning.

Total dust levels due to paint overspray (measured asarea samples) were consistenly in excess of theOSHA PEL inside the spray booth. Personalexposures to total dust did not exceed the PEL.Since most of the samples were collected inside thespray booth, the levels appear to be about the sameduring the winter and summer months.

CO levels often exceeded the ceiling limit of200 ppm. The average exposure for the nearly 8-hrsample (27 ppm) exceeded the ACGIH TLV(25 ppm) and approached the NIOSH REL of35 ppm. The levels were high enough, consistentlyenough, that some remediation is necessary tocontrol exposure. Since cars moving into and out ofthe shop were the source of the CO and since it isvery difficult to control these moving sources, thebest possible solution is to increase general buildingdilution ventilation. This increase in ventilationwould also help reduce other exposures such assolvents, isocyanates (when sprayed outside the

booth), and total dust.

Noise exposures were below the OSHA exposurelimts and the OSHA trigger limit of 85 dBA as an8-hr TWA. Noise levels did approach the NIOSHREL and the ACGIH TLV. Since body work thatproduces the highest noise levels is an inconsistentwork practice, more measurements representing awider variety of body work is recommended toincrease the baseline monitoring database. This isalso true for welding and grinding operations wheremetal exposure is the issue. The one samplecollected during this evaluation may not berepresentative of the exposure potential, even thoughthe sample results were quite low.

CONCLUSIONSIsocyanate exposures were below the variousevaluation criteria. However, an occasional sampleapproached the NIOSH REL indicating a need forprotective measures. NIOSH recommends air-supplied respirators whenever there is the potentialfor exposure to isocyanates. There are no NIOSHapproved air-purifying respirators for isocyanatesbecause isocyanates have no odor warning propertiesto indicate breakthrough of the cartridge. Studieshave shown that combination dust/mist and organiccartridges effectively stop isocyanates and that thevarious solvents, particularly n-butyl acetate, willbreak through the cartridge long before theisocyanates.32-34 Therefore, the combinationdust/mist/organic air-purifying resiprators shouldprovide adequate protection against the smallamounts of isocyanate present and the n-butylacetate odor can be used to indicate breakthrough ofthe cartridges. Eye and skin protection also needs tobe provided with isocyanate monomers.

Both solvent and total dust exposures approached,but did not exceed, the NIOSH/OSHA evaluationcriteria. Use of the combination air-purifyingrespirators during painting would also providesufficient protection for solvents and total dust. Useof gloves and eye protection will provide the neededskin and eye protection for the solvents. Eyeprotections in the entire shop should be a general


requirement due to the potential for flying objectsfrom body work (grinding and welding), detailing ,painting , polishing, etc.

The CO levels measured during the winter months,when the shop was fairly airtight, rose to levels inexcess of the NIOSH/OSHA ceiling limit and theACGIH TWA. Since vehicles need to be movedaround and in and out of the shop to keep the repairprocess going, the only real control option is toprovide general building ventilation for the shop.The only exhaust in the building occurs throughleakage into the spray booth and mixing room or ifthe exhaust fan in the southwest corner of thebuilding is turned on during any painting outside thespray booth. Outside air needs to be brought into thebuilding, tempered, and partially exhausted. TheAmerican Society of Heating, Regfrigerating andAir-Conditioning Engineers, Inc. (ASHRAE)recommends certain levels of outside air in theirguideline “Ventilation for Acceptable Indoor AirQuality,”, standard ASHRAE 62-1989.40 Thisguideline recommends 1.5 cubic feet per minute ofoutside air per square feet for auto repair shops andenclosed parking garages to control for CO.

RECOMMENDATIONSThe following recommendations are based on theenvironmental sampling results and the observationsmade during this investigation and are offered in theinterest of improving employee health and safety forall employees at Martin’s Carstar.

1. NIOSH recommends air-supplied respiratorswhen there is the potential for exposure toisocyanates. However, if air-purifying respiratorsare used, there are a few items which should benoted. First, there are no NIOSH approved air-purifying respirators for isocyanates primarilybecause isocyanates have no odor warningproperties. Studies have shown that combinationdust/mist and organic cartidges effectively stopisocyanates and that the various solvents will breakthough long before any isocyanate.32-34 Therefore, theodor property of n-butyl acetate could be used to

determine when respirators need to be replaced. Eyeand skin protection should be provided during spraypainting. At a minimum, air-purifying respirators areindicated by the organic chemical and total dustexposures.

2. General ventilation for the entire shop is neededto control CO levels in the winter. This ventilationshould meet the guidelines recommended byASHRAE 62-1989.

3. A complete respiratory protection program needsto be implemented as per 29CFR 1910.134. Many ofthe elements of the 10-point respirator plan are ineffect, but all elements must be in place includingmedical testing of workers for the ability to wearrespirators, respirator training, fit testing ofrespirators, and respirator maintenance.

4. Paint spraying should be conducted in the paintbooth as much as possible. The levels of total dustand organics can be substantial, so the best way tocontrol these exposures is to limit spraying to thebooth. When any spraying is done outside the booth,all employees in the area should be wearing theirrespirators.

5. No eating, drinking, or smoking should beallowed in the shop area.

6. Gloves should be worn when mixing paint,cleaning paint guns, or any time when bulk paintand/or solvents may come into contact with the skin.Testing for isocyanate monomers with SWYPETM

samples demonstrated isocyanate content in usedsolvent. This was confirmed by bulk sampleanalysis, therefore demonstrating the need to avoidskin contact with this solvent.

7. Noise levels should be remeasured during avariety of different body shop operations for severaldifferent days. If average noise levels exceed 85dBAas a TWA, then a comprehensive hearingconservation program needs to be implemented.


1. NIOSH [1994]. National Institute forOccupation Safety and Health. NIOSH Manual ofAnalytical Methods. 4th ed. Cincinnati, Ohio.

2. NIOSH [1972]. Criteria for arecommended standard: occupational exposure tocarbon monoxide. Cincinnati, OH: U.S.Department of Health, Education, and Welfare,Health Services and Mental HealthAdministration, National Institute forOccupational Safety and Health, DHEW (NIOSH)Publication No. 73-11000.

3. NIOSH [1977]. Occupational diseases:a guide to their recognition. Revised ed.Cincinnati, OH: U.S. Department of Health,Education, and Welfare, Public Health Service,Center for Disease Control, National Institute forOccupational Safety and Health, DHEW (NIOSH)Publication No. 77-181.

8. Additional monitoring for metal exposures shouldbe conducted during grinding and welding jobs toestablish a better metal exposure database.

REFERENCES

4. NIOSH [1979]. A guide to work-relatedness of disease. Revised ed. Cincinnati, OH:U.S. Department of Health, Education, and Welfare,Public Health Service, Center for Disease Control,National Institute for Occupational Safety andHealth, DHEW (NIOSH) Publication No. 79-116.

5. Proctor NH, Hughes JP, Fischman ML[1988]. Chemical hazards of the workplace.Philadelphia, PA: J.B. Lippincott Company.

6. ACGIH [1986]. Documentation ofthreshold limit values and biological exposureindices (with 1990 supplements). 5th ed.Cincinnati, OH: American Conference ofGovernmental Industrial Hygienists.

7. NIOSH [1994]. Pocket guide to chemicalhazards. Cincinnati, OH: U.S. Department ofHealth and Human Services, Public Health Service,

Centers for Disease Control and Prevention, NationalInstitute for Occupational Safety and Health,DHHS (NIOSH) Publication No. 94-116.

8. CDC [1988]. NIOSH recommendations foroccupational safety and health standards 1988.Atlanta, GA: U.S. Department of Health andHuman Services, Public Health Service, Centers forDisease Control, National Institute for OccupationalSafety and Health. MMWR 37 (supp. S-7).

9. Code of Federal Regulations [1989]. 29CFR 1910.1000. Washington, DC: U.S.Government Printing Office, Federal Register.

10. ACGIH [1992]. Threshold limit values andbiological exposure indices for 1992-1993.Cincinnati, OH: American Conference ofGovernmental Industrial Hygienists.

11. NRC [1985]. Emergency and continuousexposure guidance levels for selected contaminants.Washington, DC: National Research Council.National Academy Press.

12. Axelson O, Hogstedt C [1988]. On thehealth effects of solvents. In: Zenz C, ed.Occupational medicine, principles and practicalapplications. 2nd ed. Chicago, IL: Year BookMedical Publishers, Inc., p 775.

13. Cone JE [1986]. Health hazards of solvents.Occupational Medicine: State of the Art Reviews1(1):69-87.

14. Doull J, Klaassen C, Amdur MO, eds[1980]. Casarett and Doull's toxicology: the basicscience of poisons. 2nd ed. New York, NY:Macmillan Publishing Company, Inc.

15. ILO [1983]. Stewart RD, Trichloroethanes.In: Encyclopedia of Occupational Health and Safety.Vol II/l-z. Geneva: International Labour Office. p2214.

16. AIHA [1989]. Odor thresholds forchemicals with established occupational health


standards. American Industrial HygieneAssociation.

17. NIOSH [1981]. NIOSH/OSHAoccupational health guidelines for chemical hazards.Cincinnati, OH: U.S. Department of Health, andHuman Services, Public Health Service, Centers forDisease Control, National Institute for OccupationalSafety and Health, DHHS (NIOSH) Publication No.81-123.

18. NIOSH [1978]. Criteria for arecommended standard: occupational exposure todiisocyanates. Cincinnati, OH: U.S. Department ofHealth, Education, and Welfare, Public HealthService, Center for Disease Control, NationalInstitute for Occupational Safety and Health, DHEW(NIOSH) Publication No. 78-215.

19. NIOSH [1990]. Pocket guide to chemicalhazards. Cincinnati, OH: U.S. Department of Healthand Human Services, Public Health Service, Centersfor Disease Control, National Institute forOccupational Safety and Health, DHHS (NIOSH)Publication No. 90-117.

20. NIOSH [1986]. Occupational respiratorydiseases. Cincinnati, OH: U.S. Department ofHealth and Human Services, Public Health Service,Centers for Disease Control, National Institute forOccupational Safety and Health, DHHS (NIOSH)Publication No. 86-102.

21. Levy BS, Wegman DH (editors) [1988].Occupational Health: Recognizing and PreventingWork-Related Diseases. Second Edition.Boston/Toronto: Little, Brown and Company.

22. Weill H [1979]. Epidemiologic andmedical-legal aspects of occupational asthma. TheJournal of Allergy and Clinical Immunology64:662-664.

23. Porter CV, Higgins RL, Scheel LD [1975].A retrospective study of clinical, physiologic, andimmunologic changes in workers exposed to toluene

diisocyanate. American Industrial HygieneAssociation Journal 36:159-168.

24. Adams WGF [1975]. Long-term effects onthe health of men engaged in the manufacture oftolylene diisocyanate. British Journal of IndustrialMedicine 32:72-78.

25. White WG, Sugden E, Morris MJ, Zapata E[1980]. Isocyanate-induced asthma in a car factory.Lancet i:756-760.

26. Chan Yeung M, Lam S [1986].Occupational asthma. American Review ofRespiratory Disease 133:686-703.

27. NIOSH [1981]. Technical report:respiratory and immunologic evaluationof isocyanate exposure in a new manufacturingplant. Cincinnati, OH: U.S. Department of Healthand Human Services, Public Health Service, Centersfor Disease Control, National Institute forOccupational Safety and Health, DHHS (NIOSH)Publication No. 81-125.

28. Burge P [1989]. Diagnosis of occupationalasthma. Clinical and Experimental Allergy 19:649-652.

29. McKay RT, Brooks SM [1981]. Toluenediisocyanate (TDI): biochemical and physiologicstudies. American Review of Respiratory Disease123:132.

30. Zammit-Tabona M, Sherkin M, Kijek K,Chan H, Chan-Yeung M [1983]. Asthma caused bydiphenylmethane diisocyanate in foundry workers.American Review of Respiratory Disease128:226-230.

31. Siracusa A, Curradi F, Abritti G [1978].Recurrent nocturnal asthma due to toluenediisocyanate: a case report. Clinical Allergy 8:195-201.

32. Rosenberg C, Tumomi T [1984]. AirborneIsocyanates In Polyurethane Spray Painting:


Determination and Respiratory Efficiency. Amer.Ind. Hyg. Assoc. Jr 45: 117-121.

33. Vasta JF [1985]. Respirator CartridgeEvaluation for Isocyanate Containing Imron andCentari Enamals. Amer. Ind. Hyg. Assoc. Jr. 46:39-44.

34. Dharmarajan V, Lingg RD, Hackathorn DR[1986]. Evaluation of Air-Purifying Respirators forProtection Against Toluene Diisocyanate Vapors.Amer. Ind. Hyg. Assoc. Jr. 47:393-398.

35. European Chemical News [1982], 39: issue1057, p. 24.

36. Ward WD [1986]. Anatomy & physiologyof the ear: normal and damaged hearing. Chapter 5.In: Berger EH, Ward WD, Morrill JC, Royster LH,eds. Noise & hearing conservation manual. 4th ed.Akron, OH: American Industrial HygieneAssociation, pp. 177-195.

37. Ward WD, Fleer RE, Glorig A [1961].Characteristics of hearing loss produced by gunfireand by steady noise. Journal of Auditory Research1:325-356.

38. Code of Federal Regulations [1992].OSHA. 29 CFR 1910.95. Washington, DC: U.S.Government Printing Office, Federal Register.

39. NIOSH [1972]. Criteria for arecommended standard: occupational exposure tonoise. Cincinnati, OH: U.S. Department of Health,Education, and Welfare, Health Services and MentalHealth Administration, National Institute forOccupational Safety and Health, DHEW (NIOSH)Publication No. 73-11001.

40. ASHRAE [1989]. Ventilation forAcceptable Indoor Air Quality, ASHRAE 62-1989.American Society of Heating, Refigerating and Air-Conditioning Engineers, Inc. Atlanta, Georgia.


Table 1

Summary of Air Sample Results for Hexamethylene DiisocyanateMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593August 24, 1995

SAMPLE SAMPLE DESCRIPTION ON OFF SAMPLETIME(min)

VOLUMEat 1 Lpm

(m3)

HDI CONCENTRATION(::::g/m3)#

Monomer Oligomer

MCI-01 Personal-Rich-Vehicle #1 9:23 9:55 32 0.032 <31 <31

MCI-03 Personal-Rich-Vehicle #2 10:21 10:45 24 0.024 <42 <42

MCI-04 Area-Mixing Room #1 9:15 12:34 199 0.199 <5.0 <5.0

MCI-05 Personal-Rich-Vehicle #1 8:40 9:23 43 0.043 * <23

MCI-06 Personal-Rich-Vehicle #3 11:45 2:00 135 0.135 <7.4 <7.4

MCI-07 Personal-Wade 2:05 5:15 190 0.190 <5.3 <5.3

MCI-08 Area-Paint Booth #1 10:18 12:29 131 0.131 <7.6 <7.6

MCI-09 Area-Mixing Room #2 12:34 4:23 229 0.229 <4.4 <4.4

MCI-10 Area-Paint Booth #2 12:39 3:07 148 0.148 (20) <6.8

MCI-11 Area-Paint Booth #3 3:38 5:54 136 0.136 <7.4 <7.4

MCI-12 Personal-Rich-Vehicle #4 3:30 5:51 141 0.141 99 <7.1

# < values based on analytical limit of detection of 1 microgram per sample*Sample lost due to spillage NIOSH Recommended Exposure Limit, HDI Monomer: 35 :g/m3 for TWA, 140 :g/m3 for 10-min CeilingOSHA Permissible Exposure Limit: none


Table 1a

Summary of Air Sample Results for Hexamethylene DiisocyanateMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593February 29, 1996


VOLUMEat 1 Lpm

(m3)

HDI CONCENTRATION(::::g/m3)#

Monomer Oligmer

IMA-20 Area-Paint Booth 8:46 9:11 25 0.025 <80 236

IMA-21 Area-Shop-On Caleb 9:01 9:12 11 0.011 <182 273

IMA-22 Area-Paint Booth 10:42 2:06 204 0.204 <5.8 83.0

IMA-23 Personal-Wade-Paint Booth 10:42 11:15 33 0.033 <61 206

IMA-24 Personal-Cliff-Outside Booth 12:45 1:46 61 0.061 <32.8 128.0

IMA-25 Personal-Wade 1:47 4:02 135 0.135 <14.8 252.0

IMA-26 Personal-Chris-Base & Prime 3:46 4:26 40 0.04 <50.0 <50.0

IMA-27 Personal-Wade 4:02 4:29 27 0.027 <74.1 482.0

# < values based on an analytical limit of detection of 2 micrograms per sampleNIOSH Recommended Exposure Limit: HDI Monomer 35 :g/m3 for TWA, 140 :g/m3 for 10-min CeilingOSHA Permissible Exposure Limit: none


Table 2

Summary of Air Sample Results for OrganicsMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593August 24, 1995


VOLUMEat .2 Lpm

(m3)

CONCENTRATION (mg/m3) MIXTUREREL/PEL

n-ButylAcetate

Toluene Xylene EthylAcetate

CT-20 Personal-Rich-Vehicle #1 8:40 9:55 75 0.0150 30 57 5.8 6.4 0.21

CT-21 Area-Mixing Room #1 9:15 12:19 184 0.0368 5.2 6.5 1.0 1.3 0.03

CT-22 Area-Outside Booth-Westside 10:24 11:08 44 0.0088 120 16 26 9.0 0.28

CT-23 Personal-Rich-Vehicle #3 11:47 2:00 133 0.0266 49 49 15 14 0.24

CT-24 Area-Prep Area-Outside WallWest Side #1

11:55 2:50 175 0.0350 4.3 0.1 0.8 0.1 0.01

CT-25 Area-Mixing Room #2 12:20 3:34 194 0.0388 8.5 15 2.1 1.8 0.06

CT-26 Personal-Wade 2:04 5:15 191 0.0382 50 45 16 11 0.24

CT-27 Area-Prep Area-Outside WallWest Side #2

2:55 3:59 64 0.0128 117 3.4 23 6.9 0.23

CT-28 Area-Mixing Room #3 3:36 4:23 47 0.0094 57 100 19 22 0.41

CT-29 Personal-Eric 4:00 5:11 71 0.0142 48 38 32 1.4 0.24

NIOSH Recommended Exposure Limit - 8 hour TWA - mg/m3 (ppm) 710 (150) 375(100)

435(100)

1400(400)

1.0

OSHA Permissible Exposure Limit - 8 hour TWA - mg/m3 (ppm) 710 (150) 375(100)

435(100)

1400(400)

1.0


Table 2a

Summary of Air Sample Results for OrganicsMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593February 29, 1996


VOLUMEat .1 Lpm

(m3)

CONCENTRATION (mg/m3) MIXTUREREL/PEL

n-ButylAcetate

Toluene Xylene EthylAcetate

CMA 96-01 Area-Paint Booth 8:46 9:11 25 0.0025 200 36 60.0 68.0 0.56

CMA 96-02 Personal-Chris-Base &Prime

3:46 4:26 40 0.0040 38 67.5 10 4.8 0.26

CMA 96-03 Area-Shop-On Caleb 9:01 9:12 11 0.0011 60.9 21.8 13.6 10.0 0.18

CMA 96-04 Personal-Cliff-OutsideBooth

12:45 1:46 61 0.0061 98.4 105 29.5 8.2 0.49

CMA 96- 05 Area-Paint Booth 10:42 4:26 344 0.0344 113 13 32 10 0.27

CMA 96-07 Area-Mixing Room 9:15 4:30 435 0.0435 20 55 6 2.2 0.19

CMA 96-08 Personal-Wade 1:47 4:29 162 0.0162 105 68 29 10 0.40

CMA 96-09 Personal-Wade-Paint Booth 10:42 11:15 33 0.0033 54.5 112.1 16.1 6.4 0.42

NIOSH Recommended Exposure Limit - 8 hour TWA - mg/m3 (ppm) 710(150)

375(100)

435(100)

1400(400)

1.0

OSHA Permissible Exposure Limit - 8 hour TWA - mg/m3 (ppm) 710(150)

375(100)

435(100)

1400(400)

1.0


Table 3

Summary of Air Sample Results for Total DustMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593August 24, 1995


VOLUMEat 2 Lpm

(m3)

CONCENTRATION(mg/m3)

93-4352 Personal-Rich-Vehicle #1 8:40 9:55 75 0.150 ND

93-4351 Area-Paint Booth #1 10:18 12:29 131 0.262 17

93-4358 Personal-Rich-Vehicle #2 10:21 11:45 84 0.168 4.3

93-4357 Personal-Rich-Vehicle #3 11:45 2:00 135 0.270 ND

93-4356 Area-Paint Booth #2 12:39 3:07 148 0.296 19

93-4359 Personal-Wade 2:05 5:15 190 0.380 5.1

93-4354 Personal-Rich-Vehicle #4 3:30 5:51 141 0.282 6.7

93-4347 Area-Paint Booth #3 3:38 5:54 136 0.272 36

OSHA Permissible Exposure Limit = 15 mg/m3 for Total Dust


Table 3a

Summary of Air Sample Results for Total DustMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593February 29, 1996


VOLUMEat 2 Lpm

(m3)

CONCENTRATION(mg/m3)

95-3217 Area-Paint Booth 8:46 9:11 25 0.050 7

95-3216 Area-Shop-On Caleb 9:01 9:12 11 0.022 4

95-3229 Area-Paint Booth 10:42 11:44 62 0.124 5.1

95-3201 1:33 4:26 173 0.346 15.1

95-3210 Personal-Wade-Paint Booth 10:42 11:15 33 0.066 3

95-3198 Personal-Cliff-Outside Booth 12:45 1:46 61 0.122 7.5

95-3200 Personal-Wade 1:47 4:29 162 0.324 6.7

95-3206 Personal-Chris-Base & Prime 3:46 4:26 40 0.08 2

OSHA Permissible Exposure Limit = 15 mg/m3 for Total Dust


Table 4

Summary of Air Sample Results for MetalsMartin’s Carstar, Lakewood, Colorado

HETA 95-0311-2593February 29, 1996

SAMPLE # SAMPLEDESCRIPTION

SAMPLETIME(min)

VOLUMEat 2 Lpm

(m3)

CONCENTRATION (mg/m3)

Aluminum Barium Calcium Iron Magnesium Manganese Zinc

MMA 96-30 Personal-Jeff-Welding 138 0.2760 0.033 0.008 0.286 0.319 0.065 0.065 0.308

NIOSH Recommended Exposure Limit - 8 hour TWA - mg/m3 10 0.5 2 5 -- 1 5

OSHA Permissible Exposure Limit - 8 hour TWA - mg/m3 15 0.5 5 10 15 C5 5


0

100

200

300

400

500 C

arbo

n M

onox

ide

Con

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pm)

0 100 200 300 400 500 Time (minutes)

Figure 1. Carbon Monoxide Levels in Center of Shop, Martin’s Carstar 2/29/96