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Occupational Safety and Health Guide for Surface Disinfection Practices using Germicidal Ultraviolet Radiation
Thomas P. Fuller
ScD, CIH, CSP, MSPH, MBA, FAIHA
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Dr. Thomas P. Fuller has over 39 years of experience in occupational safety, radiation protection, emergency planning, industrial hygiene, infection control, and chemical hygiene. He has experience in healthcare, nuclear power plants, labor organizations, biopharmaceutical labs, manufacturing, and universities. He is currently a Professor of Occupational Safety and Health at Illinois State University. Tom is the President-Elect of the International Occupational Hygiene Association (IOHA) and Chair of the IOHA Education Committee. He is a member of the recently created American Industrial Hygiene Association (AIHA) COVID-19 Ad Hoc Response Team and the AIHA Healthcare Working Group. Dr. Fuller is a member since 2002, and twice Chair, of the AIHA Nonionizing Radiation Committee. As a member of the International Commission on Occupational Health, he serves on the Industrial Hygiene Committee and the Working Group on Infectious Occupational Agents. Tom is also on the board of the Occupational Hygiene Training Association.
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UV Radiation
• Electromagnetic waves between 100 and 400
nanometers (nm) between the x-ray and
visible light spectrums,
• UV-A (315-400 nm),
• UV-B (280-315 nm), and
• UV-C (100-280 nm)(~254 germicidal),
• UVC is typically produced in electric lamps
consisting of quartz tubes filled with an inert
gas such as argon and small quantities of
mercury.
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Health Effects
Acute Effects
– Keratoconjunctivitis (photokeratitis)
– Erythema
– Skin Photosensitization (dermatosis)
Chronic Affects
– Cataracts
– Skin Aging
– Skin Cancer
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Ultraviolet Radiation – Broad Spectrum
November 3, 2016
https://ntp.niehs.nih.gov/ntp/roc/content/listed_substances_508.pdf
Substances Listed in the Fourteenth
Report on Carcinogens
Known To Be Human Carcinogens
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Ultraviolet Radiation
Known Human Carcinogen
IARC Monographs - 2020
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https://monographs.iarc.fr/list-of-classifications
• UVC radiation poses maximum risk on human skin,
• Eyes are most sensitive to UVC and UVB radiation (photokeratitis and conjunctivitis),
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https://www.ccohs.ca/oshanswers/diseases/skin_cancer.html
Concluding Remarks (2004)
“Greater attention should be paid to the potential hazards of UVR exposure. The increasing socially driven solar exposure as well as the increasing use of artificial UVR sources is a cause for concern. In many populations, skin cancer incidence continues to rise, due in large part to poor appreciation of the risk among the generalpopulation.
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“Opinion on Biological effects of UV-C radiation relevant to health with particular reference to UV-C lamps”
Committee on Health, Environment and Emerging Risks (2017)
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• UV-C is considered to be carcinogenic to humans.
https://ec.europa.eu/health/sites/health/files/scientific_committees/scheer/docs/sche
er_o_002.pdf
Germicidal Effectiveness
• 1877 - Downes and Blunt - bacterial
property of sunlight,
• 1887 - Roux – spores destroyed by UV,
• 1935 UV radiation was widely recognized
and utilized in both industry and medicine
as an effective germicidal agent.
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UVC Effectiveness –Maximum Biological Damage
(1 nanometer= 10 Angstrom)
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UVGI LampsMercury vapor lamps are most commonly used in applications, providing 254 nm radiation
– Mercury toxicity should be considered in many applications
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Approximate time (in seconds) required at specified irradiance in microwatts per square centimeter
(µW/cm²)Radiant Energy
Required
ORGANISM
1,500 µW/cm²in seconds
(new batteries)
1,000 µW/cm²in seconds
(after 3 hours)µW.sec
cm²
BACTERIA
S. enteritidis 3 4 4,000
B. megatherium sp. (veg) *
1 1 1,300
B. megatherium sp. (spores) *
2 3 2,730
B. paratyphosus 2 3 3,200
B. subtilis* 5 7 7,100
Corynebacterium diphtheriae *
2 3 3,370
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In-Duct UVGI Single Pass Efficiency
Duct velocity = 2.2 m/sNo inactivation at velocity of 5.1 m/s
(kujundzic et al., 2006)
75%80%
91%
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Stability of SARS coronavirus in human specimens and environment and its
sensitivity to heating and UV irradiation
Conclusion: The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.
Shu-Ming Duan 1, Xin-Sheng Zhao, Rui-Fu Wen, Jing-Jing Huang, Guo-Hua Pi, Su-Xiang Zhang, Jun Han, Sheng-Li Bi, Li Ruan, Xiao-Ping Dong, SARS Research Team
Biomed Environ Sci 2003 Sep;16(3):246-5
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Uses of UVRoom and
air duct
sanitization,
Ponds, pools, lakes ozonation, aeration
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Cleaning Surfaces & Coatings
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UV Light Sources/
Inspection LampsIrradiation Chambers/
Pharmaceuticals
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Water Disinfection
• Provides safe drinking water,
• Deactivates the bacterial and viral content of surface- or ground-waters,
• Improving the chance for infants to avoid the diarrheal diseases that killed 3.8 million children under age 5 in 1993, according to UNICEF studies.
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Ventilation Systems Water Treatment Plants
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Health Care Laboratories
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Short Wave (UV-C)
Model Equipped With Typical Peak Intensity(µW/cm²)
At 10 Inches (25cm)
X-15F One 15-Watt Tube and LONGLIFE Filter Assembly
640
XX-15F Two 15-Watt Tubes and LONGLIFE Filter Assembly
1,100
UV Curing
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Additional Workers at Potential Risk from Exposure to UV Radiation
Food and drink irradiatorsHairdressers
Laboratory workers Lighting technicians
Lithographic and printing workersPolice
Outdoor workersConstruction workersPaint and resin curersPhysiotherapistsPlasma torch operatorsArc WeldersFarmers
Some Devices Emitting UV Radiation
Bactericidal lampsBlack light lamps
Carbon, xenon and other arcsDental polymerizing equipment
Fluorescence equipmentHydrogen and deuterium lamps
Metal halide lampsMercury lampsPlasma torchesPhototherapy lamps Printing ink polymerizing equipmentWelding equipment
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Wavelength Model Equipped With
Typical PeakIntensity(µW/cm2)
At 10 Inches(25cm)
Germicidal ShortWave (UV-C)
X-15GOne 15-Watt Tube,
Not Filtered820
X-30GOne 30-Watt Tube,
Not Filtered1,850
XX-15GTwo 15-Watt Tubes,
Not Filtered1,550
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https://www.npr.org/sections/health-shots/2020/07/13/890387205/coronavirus-sparks-new-interest-in-using-
ultraviolet-light-to-disinfect-indoor-a 26
Exaggerated risk of transmission of COVID-19 by fomites
• Lancet Infect Dis 2020, Published Online July 3, 2020 https://doi.org/10.1016/S1473-3099(20)30561-2
• Emanuel Goldman, Professor of Microbiology, Biochemistry and Molecular
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Hundreds of scientists say there is evidence that the novel coronavirus in
smaller particles in the air can infect people and are calling for the World
Health Organization to revise its recommendations, the New York Times
reported on Saturday.
The WHO has said the coronavirus spreads primarily from person to person
through small droplets from the nose or mouth, which are expelled when a
person with COVID-19 coughs, sneezes or speaks.
In an open letter to the United Nations agency, which the researchers plan
to publish in a scientific journal next week, 239 scientists in 32 countries
outlined the evidence showing smaller particles can infect people, the NYT
said.
Hundreds of scientists say coronavirus is airborne, ask WHO to revise recommendations
https://www.cbc.ca/news/health/scientists-who-coronavirus-airborne-1.5638444
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Usefulness of UV as a germicide for air?
As the ventilation increases, the relative effectiveness of UV irradiation diminishes significantly.
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Evaluation
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(For 264 nm = 6.0 mJ/cm2)
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UV Irradiance Determination
• Mathematical modeling of UV emission patterns and levels,
• Validation measurements of to ensure adequate germicidal activity,
• Measurements to determine compliance occupational safety and health guidelines,
• Records maintained in logbook with date, time, detector readings, overexposure incidents, and methods used.
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Making Measurements
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Meter Recommendations
• UVC narrow band meters with diffusing optics are most practical,
• Users must be aware of the spectral response of the detector and account for limitations,
• Be aware of the angular response of the meter unless measurement geometries are representative of exposure conditions and do not change,
• Out-of-band spectral response does not significantly affect detector response unless particularly close to alternate sources. 36
Germicidal Effectiveness Measurements
– Take readings at a variety of locations to attempt to approximate an average irradiance level,
– Point the radiometer probe in a variety of directions to estimate an average for each location,
– If available, use chemical actinometry to verify measurement results,
– Compare results to ensure upper level averages are between (30 -50 μW.cm2).
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Occupational Measurements
– Calibrated UV meter or dosimeter,
– Measurements taken at eye level,
– Identify peak levels
– Various locations in the room,
– Account for occupant activities and durations,
– Identify and correct room “hot spots”,
– Taken by personnel trained in UV measurements,
– Compared to CDC/NIOSH RELs or ACGIH TLVs.38
May 2009
• Evaluate 10 broadband and narrowband meters against spectroradiometers for angular response, spectral response, and linearity,
• Improve awareness of the role of detector characteristics in accuracy of health hazard assessments of UVC lamps. 39
Controls
Engineering
– Enclosures, interlocks, beam shields, sunscreens, distance
Administrative
– Policies, procedures, warning lights and signs, training, monitoring, surveillance, time
PPE
– Eyewear, clothing, hats, sunscreen lotion, gloves
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Administrative Controls
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PPE % UVC Blocked
• Tech Splash Mask
• Red Goggles
• Blue Hoods
• Two Ply Blue Hoods
• Blue Smock
• Labcoat
• Labcoat after 10
washings
> 99.9
> 99.9
75
95
82
90
80
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PPE
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PPE Issues
• Inadequate protection
factors,
• Difficult to enforce,
• Confusing to workers,
• Unavailable supply,
• Need to test and document
• Protection factors change
with use and washing
• Insufficient training.
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UV Fixtures/System Installation
• Shortage of qualified installers,
• Installers should have training on installation and placement,
• Engineers, industrial hygienists, health professionals, and health physicists may be consulted,
• System design should be coordinated with infection control criteria, ventilation systems, and surgical suite design.
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Common UV System Problems
• Poor preventive maintenance,
• No on/off switches for maintenance,
• Protective louvers bent or missing,
• No warning labels or warning signs,
• No worker training,
• No lock-out tag-out procedures,
• Reflective paints and equipment increasing exposures to occupied spaces,
• Improper installation.46
Future Directions
• Regulatory controls over UVC emitting devices (labeling, worker protections, user and maintenance instructions),
• Guidelines and equipment for conducting occupational exposure assessments,
• Regulatory enforcement of occupational exposure limits and medical surveillance of exposed workers.
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Select References• IARC, International Agency for Research on Cancer, Agents Classified by the IARC Monographs, Volumes 1-125 (2020) Geneva https://monographs.iarc.fr/list-of-
classifications Accessed July 15,2020.
•
• National Toxicology Program (2016) 14th Report on Carcinogens (2016) U.S. Department of Health and Human Services, Substances Profiles, National Toxicology Program, https://ntp.niehs.nih.gov/ntp/roc/content/introduction_508.pdf Accessed July 15, 2020.
•
•
• Canadian Center for Occupational Health and Safety, Skin Cancer and Sunlight (2020) https://www.ccohs.ca/oshanswers/diseases/skin_cancer.html Accessed July 15, 2020.
•
• SCHEER, Opinion on Biological effects of UV-C radiation relevant to health with particular reference to UV-C lamps, Scientific Committee on Health, Environment and Emerging Risks, European Commission (2017) https://ec.europa.eu/health/sites/health/files/scientific_committees/scheer/docs/scheer_o_002.pdf
•
• Duan, S., Zhao, X., Wen, R., Huang, J., Pi, G., Zhang, S., Han, J., Bi, S., Ruan, L., Dong, X., Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation, Biomed Environ Sci 2003 Sep;16(3):246-5
•
• Card, K., Crozier, D., Dhawan, A., Dinh, M., Dolson, E., Farrokhian, N., Gopalakrishnan, V., Ho, E., King, E., Krishnan, N., (2020) UV sterilization of personal protective equipment with idle laboratory biosafety cabinets during the Covid-19 pandemic. medRxiv. https://doi.org/10.1101/2020.03.25.20043489
•
• ACGIH 2020 Threshold Limit Values (TLV®) and Biological Exposure Indices (BEIs®), ACGIH, Cincinnati, OH, 2020, pp. 155–160
•
• International Commission on Non-Ionizing Radiation Protection (ICNIRP), “Guidelines on Limits of Exposure to Ultraviolet Radiation of Wavelengths Between 180 nm and 400 nm (Incoherent Optical Radiation),” Health Phys. 87, 171–186 (2004).
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Select References• Dreiling J. (2008). An Evaluation Of Ultraviolet Germicidal Irradiation (UVGI) Technology In Health Care Facilities, MS Thesis, Kansas State
University.
• Bernstein JA. (2006). Health effects of ultraviolet irradiation in asthmatic children’s homes, J Asthma 43:255-262.
• Jamriska M et al. (2000). Effect of ventilation and Filtration on Submicrometer Particles in an Indoor Environment Indoor Air 10(1):19-26
• Kujundzic E et al. (2007). Ultraviolet germicidal irradiation inactivation of airborne fungal spores and bacteria in upper-room air and in-duct configurations, JEES 6:1-9.
• Kujundzic E et al. (2006). Air cleaners and upper-room air UV germicidal irradiation for controlling airborne bacteria and fungal spores, JOEH 3:536-546.
• Kujundzic E et al. (2005). Effects of ceiling-mounted HEPA-UV air filters on airborne bacteria concentrations in an indoor therapy pool building, JAWM 55:210-218.
• Mendell MJ et al. (2002). Indoor particles and symptoms among office workers: results from a double-blind cross-over study, Epidemiology 13:296-304.
• Menzies D et al. (2003). Effect of ultraviolet germicidal lights installed in office ventilation systems on workers’ health and wellbeing: double-blind multiple cross-over trial, The Lancet 362:1785-1791.
• Perkins et al. (1947). Effect of ultra-violet irradiation of classrooms on spread of measles in large rural central schools, Amer J Public Health 73:529-537.
• Riley et al. (1962). Infectiousness of air from a tuberculosis ward, Amer Rev Respir Disease 85:511-525.
• Xu P et al. (2005). Impact of environmental factors on efficacy of upper-room air ultraviolet germicidal irradiation for inactivating airborne Mycobacteria, ES &T, 39:9656-9664.
• Xu P et al. (2003). Efficacy of ultraviolet germicidal irradiation of upper-room air in inactivating bacterial spores and Mycobacteria in full-scale studies, Atmos Environ 37:405-419.
• Peccia, J. and Hernandez, M. (2001). Photoreactivation in Airborne Mycobacterium parafortuitum. Appl. Environ. Microbiol. 67:4225-4232.
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