Occupational health risk assessment of airborne formaldehyde in medical laboratories

The professional use of formaldehyde is a major occupational health concern in medical laboratory operations. Quantification of various risks associated with chronic exposure to formaldehyde may help in understanding the related hazards. This study designed to assess the health risks associated with inhalation exposure to formaldehyde involving biological, cancer, and non-cancer risks in medical laboratories. This study was performed in the hospital laboratories at Semnan Medical Sciences University. Risk assessment was performed in pathology, bacteriology, hematology, biochemistry, and serology laboratories with 30 employees, using formaldehyde in their daily routine operations. We determined area and personal exposures to airborne contaminant, applied standard air sampling, and analytical method recommended by National Institute of Occupational Safety and Health (NIOSH). We addressed formaldehyde-specific hazard by estimating peak blood level, life cancer risk, and the hazard quotient of non-cancer risks, adapted from Environmental Protection Agency (EPA) assessment method. The airborne formaldehyde concentrations in the laboratory personal samples ranged 0.0156-0.5940 ppm (mean = 0.195 ppm, SD = 0.048) and area exposure ranged 0.0285-1.0810 ppm (mean = 0.462 ppm, SD = 0.087). Based on workplace exposure, peak blood levels of formaldehyde were estimated at minimum 0.0026 mg/l to maximum 0.152 mg/l (mean = 0.015 mg/l, SD = 0.016). The mean cancer risk levels in terms of area and personal exposures were estimated respectively at 3.93 E - 8 μg/m³ and 1.84 E - 4 μg/m³, and for the non-cancer risk levels of the same exposures measured respectively at 0.03 μg/m³ and 0.07 μg/m³. Formaldehyde levels were significantly higher among laboratory employees, especially bacteriology workers. Exposure and risk could be minimized by strengthening control measures including the use of management controls, engineering controls, and respiratory protection equipment to reduce exposure levels of all workers to less than the allowed exposure limits and improve indoor air quality in the workplace.