FEATURE An assessment of occupational exposures to ultraviolet radiation from transilluminator light boxes in the course of biomedical research procedures

Transilluminators, used in biomedical research, can be a significant source of occupational exposure to ultraviolet radiation (UVR). Ultraviolet exposure can result in biological effects ranging from photoker- atitis to erythema. In this study, a comprehensive risk assessment evaluation of transilluminators was performed. The survey data revealed 80% of transilluminators units had some type of engineering control designed into the unit and over 75% compliance with the use of PPE. Self reported adverse health effect such as eye and skin injuries were reported and found significant variable correlated to the presence of a shieldedcoveronthetransilluminatorsandtheavailabilityofafullfaceshield.Whilepercentcomplianceis high, recommendation can be made to reduce the possibility of overexposure by instituting a UVR specific training awareness program, purchasing and installing shield covers and implementing a purchasing program to require the purchase of UV transilluminator units to have engineering controls specifically the shield covers.

By Chavaun Harper, INTRODUCTION BACKGROUND AND SIGNIFICANCE Robert J. Emery, Dennis M. Casserly Human exposure to ultraviolet radia- Ultraviolet radiation is a form of non- tion (UVR) can occur naturally ionizing radiation with wavelengths through sun illumination during out- ranging from 100 to 400 nanometers door activity or through exposure to (nm). Ultraviolet radiation can be cate- Chavaun Harper, M.S., is affiliated artificial sources either voluntarily or gorized into spectral bands: The UV-A with The University of Houston-Clear occupationally. The potential detri- region exhibits wavelengths between Lake, 4211 Elgin Rm 183, Houston, mental effects of exposure to ultravio- 315 and 400 nm, UV-B in the region TX 77204, USA (Tel.: +713 743 1200; let radiation to the human skin and of 280–315 nm and UV-C wavelengths fax: +713 743 5859; e-mail: ccharper@ eyes have been well documented.1–4 between 100 and 280 nm. The wave- uh.edu). Recent growth in the area of biome- length range below 315 nm is referred dical research involving the applica- to as the actinic range where most Robert J. Emery, Dr.P.H., is affiliated tion of UVR is another area of chemical and biological reactions with The University of Texas Health possible occupational exposure. occur. Science Center at Houston, Depart- Occupational exposure to UVR dur- Potential adverse health effects are ment of Environmental Health and ing the analysis of electrophoresis associated with exposure to ultraviolet Safety, 6516 M.D. Anderson Blvd, gels using UVR emitting transillumi- radiation include effects on the eyes, P.O. Box 20068, Houston, TX, nators, commonly referred to as ‘‘light skin and immune system. The response 77030, USA. boxes’’ have not been well character- of the eye to UVR can manifests as ized. In this study UV transillumina- photokeratitis, photoconjunctivitis, Dennis M. Casserly, Ph.D., is affiliated tors were evaluated by means of a retinal burns, cancer and cataracts. with The University of Houston-Clear comprehensive risk assessment sur- Photokeratitis and photoconjunctivitis Lake, 2700 Bay Area Blvd., #59, Hous- vey to determine the level of UVR can result from effects of acute, high ton, TX 77058, USA. exposure. intensity exposure and generate a

16 ß Division of Chemical Health and Safety of the American Chemical Society 1871-5532/$32.00 Published by Elsevier Inc. doi:10.1016/j.jchas.2007.08.002 feeling of sand in the eye, lacrimina- tion, and severe pain sometimes referred to as ‘‘welder’s flash’’ or ‘‘arc eye’’ which are commonly temporary without permanent damage.5 The most common skin adverse reaction to UVR exposure manifests as erythema or sunburn although chronic exposure to solar radiation increases skin aging. Erythema distress can range from a reddening to blistering of the skin.1 The absorption of ultraviolet radiation, namely UV-B, causes damage to the human body at the cellular level. The immune system is impacted when ultraviolet radiation is absorbed into Figure 1. UV transilluminator with a shield and filter protector. cellular components namely DNA and creates mutations by way of thiamine dimers. Although most of the ultravio- box that encloses a UV light source the transilluminator creating a dark let exposure humans receive is from with filter surface on top of the box room (Figure 2). Other imaging sys- solar radiation, the same adverse (Figure 1). This equipment is used tems completely enclose the transillu- effects can occur if exposed to UV in in biomedical research to visualize minator and combine the photography the workplace. genetic material. Studies conducted equipment/software into one unit Though no Occupational Health by Klein10 and Akbar-Khanzadeh known as bioimaging systems and Safety Administration (OSHA) and Jahangir-Blourchain11 measured (Figure 3). Thus the exposure to regulatory standard exists for exposure UVR output from transilluminators UVR is virtually eliminated because to UVR, two other health and safety utilized in biomedical research and the UV light source is enclosed and related entities suggested UVR expo- both concluded that exposure mea- interlocked therefore the ultraviolet sure limits. The American Conference surements taken at their study sites light will not when the unit is open. of Governmental Industrial Hygienists exceeded the 8-hour ACGIH TLV. As technology develops, additional (ACGIH) suggests an exposure thresh- Additionally Cazzuli and Giroletti12 safety devices or features will be intro- 2 old limit value of 0.1 mW cmÀ for the measured UV exposure from several duced to eliminate the UVR hazard. actinic region for an 8-hour period.6 instruments used in chemical, genetic The National Institute of Occupational and microbiology and biology includ- Health and Safety (NIOSH) recom- ing UV transilluminators, which were mends less than one minute of expo- classified as a high risk of exposure to 2 7 sure to100 mW cmÀ at 254 nm. The eyes and hands. International Commission on Non- UV transilluminator’s safety features ionizing Radiation Protection5 has evolved from stickered warnings to established exposure limits (EL) for protective shields to interlocks. The unprotected eyes and skin not to shielding device is made of a thick 2 exceed 30 J mÀ . The Federal Register transparent plastic, some having an contains two citations that requires additional UV specific coating. Manu- warning labels for the use of UVR facturers of UV transilluminators place emitting devices under the Depart- warnings on most units indicating that ment of Health and Human Services exposure to ultraviolet radiation will U.S. Food and Drug Administration: result if the unit is not used in accor- the mercury vapor discharge lamp dance with the manufacturers’ instruc- under section 21 CFR part 1040.38 tions. The same warning is also and sun lamps used in tanning beds included in the unit’s instruction man- 21 CFR part 1040.2.9 Though no legal ual. Some shielding devices are hinged standard applies to the UVR exposure to allow for easier access and manip- produced by UV transilluminators, ulation of the gel which if used in this guidelines are available and can be manner can lead to UVR exposure applied to light box use. while other unit incorporate interlocks UV transilluminators, or light boxes, that require the shield to be in down are commonly used lab equipment that position before the UV light will work. emit wavelengths in the actinic range. As an enclosure option, a black curtain Figure 2. UV transilluminator with a A UV transilluminator unit such as a can be used to surround and enclose photocurtain.

Journal of Chemical Health & Safety, March/April 2008 17 tion decisions, purchasing practices tories identified as using and housing and oversight to maintain scheduling UV transilluminators. As part of the and training to reduce the hazard. Environmental Health and Safety Personal protective equipment is the Department’s routine surveillance pro- last option to protect the user from the gram, a database of UV light sources hazard because it is a physical barrier was maintained. By accessing the data- worn by the user to separating the user base, UV transilluminator unit loca- from the hazard. PPE can be cumber- tions were recorded and used as the some, bulky and a burden on the user. sample pool. One member from each For those reasons it is the last option laboratory was observed using the employed. PPE to shield the face, eyes transilluminator. Laboratory person- and neck can be found by using UV nel were defined as including a labora- rated full face shield or UV rated safety tory manager, a technician, assistant or glasses. To guard the exposed upper a graduate student. Laboratory person- extremities, PPE includes gloves to nel were chosen to participate based cover exposed hands and long sleeves on availability and prior familiarity to cover exposed arms and wrists. A using the transilluminators. During study by Gazik et al.13 found that latex the study, laboratory personnel were Figure 3. Bioimaging system. UV tran- and nitrile material gloves reduced observed using the transilluminator silluminators is located inside pullout UVR hand exposure but vinyl did and answered the study questionnaire. drawer. not. Overall, a need for personal pro- Answers to the questions were noted tective equipment is essential to elim- by marking ‘‘yes’’ or ‘‘no’’ on the survey Once any hazards are identified, inate or greatly reduce the amount of form and by self reporting to the ques- engineering and administrative con- exposure from UV light boxes. tions that required explanation. Per- trols along with personal protective In the studies by Klein10 and Akbar- sonnel in labs using UV- equipment (PPE) can be implemented Khanzadeh and Jahangir-Blourchian11 transilluminators were asked to self to reduce hazards to the workers. Each both collected measurements of UVR report via the questionnaire the nor- of these controls and equipment has output from UV transilluminators mal practices while using the unit. advantages and limitations when without any shielding in place which applied to reducing UVR. Engineering demonstrating a possible UV overex- controls are first applied to eliminate posure could occur from using a UV RESULTS the hazard in the equipment design by transilluminator if the shield covering providing a shield cover or interlocks is removed from the unit which vio- Biomedical research laboratories in or by isolating the area where the lates the manufacturers’ user instruc- the study site were inspected for hous- equipment will be used. tions and exposes the user to the ing and use of UV transilluminators. Administrative controls are a second hazard. Disabling a unit by removing Two types of UV transilluminators option utilized to reduce the possibility the shielding is not representative of (n = 62) used in biomedical research of hazard exposure. Substituting alter- actual laboratory usage; therefore per- were found during the inspections: 37 native chemical solutions that allow forming an actual UVR risk assessment tabletop transilluminators and 25 bioi- DNA to fluoresce when exposed to is needed. Upon reviewing available maging systems. Of the 37 tabletop visible light thus eliminating the use literature, a set of recognized prudent transilluminators units, 27 of the units hazardous chemicals and UV light, safety practices were assembled to cre- had shielding while 10 did not have however they are not preferred by ate a single comprehensive risk assess- shielding as depicted in Table 1. researchers due to weak bonding with ment survey tool to evaluate the type of Engineering and administrative con- nucleic acids, producing a lack of unit used, engineering controls, and trols are shown in Table 1 shows as the visual intensity. Implementing a pur- safety procedures implemented. The frequency of light boxes that have chasing policy that requires the pur- purpose of this study is to determine applied various engineering controls chase of units meet specific safety the risk of UVR exposure to workers and the practice of substituting the standards and scheduling the use of using transilluminators in normal fluorescent hazardous chemical, ethi- UVR in time periods where limited laboratory settings through the use a dium bromide for a less hazardous numbers of workers are present are comprehensive risk assessment survey chemical. examples of administrative control. tool. Personal protective equipment Training involving the use of UV tran- available for use was reviewed at the silluminators should incorporate UVR time of inspection. The type of PPE and hazard identification, adverse health MATERIALS AND METHODS percent compliance of use of the PPE effect recognition and familiarizing was assessed and results are summar- the worker with the manufacturer’s The study site was a medical complex ized in Figure 4. instruction. Administrative controls and the study population included bio- Self reported adverse health effects, rely on personnel to enforce substitu- medical research workers and labora- shown in Table 2 indicates that 47

18 Journal of Chemical Health & Safety, March/April 2008 Table 1. Transilluminator Engineering and Administrative Control Frequency DISCUSSION Engineering Controls Number of Units (n = 62) Self reported adverse health effects Bio imaging systems (enclosed) 25 such as an eye injury (photokeratitis Counter top units 37 or photoconjunctivitis) or skin injury Shielded 27 (erytherma) were reported. Of the sur- Non-shielded 10 veyed users, three self reported both Total number of units 62 eye and skin injury, four self reported Interlocks 13 eye injury and six reported skin injury. Timers 5 Survey respondents were not asked to detail what type of transilluminator the Warning labels injury occurred from, how the unit was Manufacturer applied on unit 38 being used or when the injury Safety applied on unit 10 occurred. Safety applied on access entry point 30 The results of this study indicated Isolation 33 that shielding on UV transilluminator Photo curtain 18 unit is a significant variable in reducing exposure to UVR. In logistic regression Administrative controls analyses, self reported adverse effects Substitution 1 were compared across levels of four independent variables, and shielding Table 2. Self Reported Adverse Health a large amount of variability in self presence on the unit and the availabil- Effects from UV Transilluminator Use reported adverse health effects and ity of a full face shield were the vari- Number of Self no other variables (separate area, or ables shown to be a significant factor. Body Part Reported Injuries gloves) met the 0.10 significant level Having a separate area available for Affected (n = 57) for inclusion in the model. Analyses usage and having gloves available for were done using SAS Statistical Ana- use did not affect the occurrence of self Eye 4 lysis Software Version 8.2. reported adverse health effects. Skin 6 Noted during the survey process While the strong relationship Both eye and skin 3 were additional hazards not accounted between self reported adverse health None 47 for during the initial risk assessment. effects and shielded units is very plau- Unprotected sharps (razor blades) sible, it could also be due to several users experienced no injury, 4 users were observed in close proximity to factors that could not be controlled experienced ocular injury, 6 users the UV light boxes in 16 of the 62 units given the data used in this analysis. experienced skin injury while 3 users surveyed. Razor blades are used to This apparent presence of the shield reported both eye and skin injury. physically cut out the DNA band of could be a confounder since fewer The stepwise logistic regression interest for further investigation. Also adverse health effects are expected model analysis excluded all indepen- noted, 5 of the 37 countertop transil- when using a shield. Such an effect dent variables for the model except luminators were placed on cabinet could be accounted for if constant Shielding 1 (p-value = 0.01) and tops immediately inside the laboratory observations were applied rather than PPE2 (p-value = 0.07). The presence entry and removable filter protectors relying on self reporting. The of a shield on the instrument and the were observed being used as a shield by Hawthorne effect defined as the ten- availability of face shield accounted for 4 laboratory personnel. dency for employees to so the job in a nonroutine manner while being observed, could very well have influ- enced the reluctance of the lab person- nel to self report. The survey does not specify a time period of when the events could have occurred and the survey did not indicate to the lab per- sonnel to reveal which type of transil- luminator they received an injury from or if the unit was being used impro- perly. Lastly, the small number of respondents limited the analyses that could be done with adequate power. With a larger dataset, more variables could be more accurately tested for Figure 4. Percentage of user compliance regarding personal protective equipment. inclusion into a regression model.

Journal of Chemical Health & Safety, March/April 2008 19 Technological advancement in the No record of UVR specific training 3. Moehrle, M.; Heinrich, L.; Schmid, A.; design of UV transilluminators has was accounted for although two labs Garbe, C. Extreme UV exposure of resulted in incorporating engineering did have posted warnings of the professional cyclists. Dermatology, controls into the units. Engineering hazards associated with UVR. 2000, 201, 44–45. 4. Kirschke, D. L.; Jones, T. F.; Smith, N. controls such as UV enclosure, shield- M.; Schaffner, W. Photokeratitis and ing, timers, interlocks and warning CONCLUSION UV-radiation burns associated with labels are observed in the majority of damaged metal halide lamps. Arch. the transilluminators in the survey The risk assessment survey proved to Pediatr. Adolesc. Med. 2004, 158, population. Enclosed and shielded be a useful tool to provided adequate 372–376. units account for 84% of the light box questions for performing a compre- 5. The International Commission of Non- Ionizing Radiation Protection. Guide- population leaving only 16% units with- hensive risk assessment evaluation of out some type of an engineering control. lines on Limits of Exposure To Ultra- UVR exposure from transilluminators. violet Radiation of Wavelengths Administrative controls were prac- Technological advances have inte- ticed in one laboratory. The lab person- Between 180 nm and 400 nm (Inco- grated engineering controls into the herent Optical Radiation). Health nel have substituted the fluorescence design of UV transilluminators thus Phys. 2004, 87(2), 171–86. chemical, ethidium bromide, to an reducing and sometime eliminating 6. ACGIH. Threshold Limit Values for alternative chemical (EvaGreen) that the hazardous UVR exposure. Of the Chemical Substances and Physical does not require the use of UVR. surveyed population, 84% of the tran- Agents and Biological Exposure Indi- A large percentage of compliance silluminators have engineering con- cies. ACGIH: Cincinnati, Ohio, 2005, was seen in the use of PPE associated trols in the form of enclosed UVR or pp. 163–6. 7. NIOSH. Criteria for a Recommended with transilluminators. Laboratory attached shielding to reduce the expo- coats and gloves were observed in Standard Occupational Exposure to sure hazard. Ultraviolet Radiation. DHHS use in 90% and 89% of the survey PPE compliance was above 75% for population, respectively. Face and (NIOSH) Publication No. 73-11009; using equipment to protect exposed 1972. eye protection was observed by using hands, eyes and face. Use of some form 8. Food and Drug Administration Depart- full face shield or safety glasses of of eye protection (full face shield or ment of Health Human Services. Per- which 26% and 46% respectively, of safety glasses) was greater than 90%. formance Standards For Light- users comply. The use of gloves was 90% and the use Emitting Products: U.S. Government Behavior observed while performing of laboratory coat was 89% compliant. Printing Office; 21 CFR Part 1040.30; the survey revealed a possibility for To further reduce the possible UVR revised April 1991. 9. Food and Drug Administration Depart- exposure not previously discussed. exposure, recommendations can be Some manufacturers have an acces- ment of Health Human Services. Per- made to develop and implement formance Standards For Light- sory called a filter protector which is UVR specific awareness training, a thin UV transmittable plastic cover- Emitting Products: U.S. Government appropriate funds for the purchase Printing Office; 21 CFR Part 1040.20; ing that is designed to be placed over and installation of shielding covers revised April 1991. the top of the UV transilluminator fil- for transilluminators currently without 10. Klein, R. C. Ultraviolet light hazards ter surface to protect the filter surface shielding and to implement a purchas- from transilluminators. Health Phys. from cuts and scratches. Four surveyed ing plan that requires engineering con- 2000, 78, S48–S50. lab personnel members were observed trols such as shielding, interlocks or 11. Akbar-Khanzadeh, F.; Jahangir- placing the gels on the nonshielded complete enclosure before the pur- Blourchain, M. Ultraviolet radiation exposure from UV-transilluminators. transilluminator surfaces, positioning chase of new UV transilluminators. the filter protector as a body shield Appl. Occup. Environ. Hyg. 2005, 2, and then turning on the UV light 493–496. switch. When questioned about the REFERENCES 12. Cazzuli, O.; Giroleti, E. Laboratory UV exposure: Risk assessment and protec- practice of using the filter protector 1. Hitchcock, R. T.; Murray, W. E.; Patterson, R. M.& Rockwell, R. J., Jr. tive measures. Photochem. Photobiol. as a body shield, the respondents sta- 2004, 80, 548–553. ted that they thought the filter protec- Nonionizing radiation., In R. DiNardi Salvatore (Ed.), The Occupational En- 13. Gazdik, E. A.; Rosenthal, F. S.; Wang, tor was a shield to protect them. The vironment: It’s Evaluation, Control W.-H. Determination of the attenua- individuals were shown the warning and Management. (2nd ed.). AIHA tion properties of laboratory gloves labels, informed of how to properly Press: Virginia, 1997. exposed to an ultraviolet transillumi- use the filter protector and educated 2. Woodcock, R. C. Blinded by the light. nator. Appl. Occup. Environ. Hyg. about the use of PPE. Occup. Health Saf. 1998, 67, 26–28. 2004, 1, 391–402.

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