A long-term study of the development of N2O controls at a pediatric dental facility.
Crouch-KG; McGlothlin-JD; Johnston-OE
Am Ind Hyg Assoc J 2000 Sep/Oct; 61(5):753-756
A review is given of National Institute for Occupational Safety and Health (NIOSH) efforts to control N2O at a pediatric dental operatory from 1978 to the present. Measurements of N2O concentrations were made on four occasions before and after installation of different controls, using an infrared analyzer. Air velocity and volumetric flow measurements also were taken. Video imaging was done in some cases simultaneously with real-time N2O measurements to correlate work practices with exposure data. An infrared imaging system was used to identify sources of N2O. Critical components of resulting recommendations for control include monitoring of N2O concentrations; use of engineering controls, such as a scavenging mask, an effective dilution ventilation system, and auxiliary exhaust; good work practices; maintenance of the equipment; and worker education. Data presented strongly supports the hypothesis that better implementation of controls leads to reduction of N2O exposures. N2O concentrations were reduced by a factor of 61 from their initial levels. The current NIOSH recommended exposure limit of 25 ppm TWA during the time of N2O administration appears to be achievable.
Dentists; Dentistry; Dental-materials; Nitrous-oxides; Exposure-limits; Exposure-levels; Exposure-methods; Anesthetics; Ventilation-systems; Engineering-controls
U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 4676 Columbia Parkway--R5, Cincinnati, Ohio 45226
American Industrial Hygiene Association Journal