Health hazard evaluation report: HETA-2001-0483-2884, Immigration and Naturalization Service, San Diego, California.
In August 2001, the National Institute for Occupational Safety and Health (NIOSH) received a request from the San Diego District of the Immigration and Naturalization Service (INS) for technical assistance in evaluating reports of skin and eye problems among Immigrations Inspectors at the San Diego International Airport. Shortly after moving into a newly renovated space at the airport, 9 of 12 Inspectors reported symptoms of eye irritation, itching, burning, and redness. Some also reported skin rash. An indoor environmental quality investigation did not identify any chemical or biological contaminants that could be considered as the source of the problem. Further investigation revealed that new ultraviolet (UV) lamps had been purchased. UV lamps are routinely used to verify the authenticity of documents submitted by international passengers. The new lamps were found to contain two tubes-one UV-A tube and one UV-C tube. Because the UV-C tube is not needed for document verification and was considered to be a potential cause of the reported health problems, it was removed from the lamps. NIOSH was then asked to further evaluate potential UV radiation exposures to INS Inspectors. NIOSH visited the facility and measured UV-C irradiance levels at one of the booths where the lamps were used. A UV-C tube was re-installed prior to measurement. At 254 nanometers (nm), the predominant UV wavelength emitted by the UV-C lamp, irradiance levels exceeded 465 microwatts per square centimeter (uW/cm2) at ten inches from the lamp. This irradiance level results in a permissible exposure time of less than 15 seconds for workers with unprotected eyes and skin. At 18 inches from the lamp and a height of 56 inches above the floor (approximating the potential exposure to the eyes) the measured irradiance was around 5 FW/cm2 corresponding with a permissible exposure time of approximately 20 minutes. Thus, under typical conditions of use, employees could be overexposed to UV-C radiation in seconds to minutes depending on the actual distance of the unprotected eyes or skin to the lamp. UV-A irradiance levels were later measured on one unit at an off-site location. Under typical conditions of use, results indicated that exposure to the employees' eyes would not likely exceed the applicable occupational exposure limits for UV-A radiation. A review of medical information for the affected employees revealed that three of nine inspectors with eye symptoms also reported rash associated with itching, irritation, and reddening of the skin, primarily on the face, neck, and forearms. Eye symptoms reported by employees included blurred vision, burning eyes, intense pain, watery eyes, swollen eyes, and temporary loss of vision. Six employees filed "CA-1" forms (notification of work-related illness or injury), and all six were diagnosed and treated for conjunctivitis; three employees were also diagnosed with "allergic dermatitis." Three of the nine symptomatic Inspectors did not file a CA-1 but sought medical attention privately. Those records were not available for review, although all three reported that they had been diagnosed with conjunctivitis by their physicians. Most workers' symptoms reportedly resolved within 3-6 days. Two of the three Inspectors who did not report any eye or skin symptoms indicated that they had not used the lamps. There were no further reports of skin or eye problems since the UV-C tubes were removed from the lamps. The environmental measurements indicate that the UV lamps used by INS Inspectors at the San Diego International Airport in March 2001 emitted high levels of UV-C radiation, representing a health hazard to those with close and direct contact with the lamps. The symptoms and signs reported by INS Inspectors are consistent with occupationally-induced photokeratitis and conjunctivitis due to UV-C overexposure. Recommendations are made in this report to prevent future problems resulting from the use of UV lamps for document verification.