Workers' exposures to n-propyl bromide at an aerospace components manufacturer.
Hanley-KW; Dunn-K; Sollberger-R
NIOSH 2006 Nov; :1-25
The National Institute for Occupational Safety and Health (NIOSH) conducted a field study at an aerospace component manufacturing plant where n-propyl bromide (nPB) was used as a vapor degreasing solvent. Workers' breathing zone and exhaled breath concentrations of nPB and isopropyl bromide (iPB), and urinary metabolite concentrations of bromide and propyl mercapturic acid were measured. n-Propyl bromide has been marketed to replace ozone depleting solvents 1,1,I-trichloroethane and freons, as well as suspect carcinogens trichloroethylene and methylene chloride; chemicals that were commonly used in industry. Very little data are currently available to evaluate human exposure to nPB. However, there is concern that nPB may be a hematological, reproductive, or neurological toxin, based on analogy to other brominated-propanes, animal toxicity studies, and a limited number of case studies. Full-shift exposure to nPB in air samples collected in workers' breathing zones ranged from 0.19 to 2.6 parts per million (ppm). All of the workers were exposed to nPB at levels below the American Conference of Governmental Industrial Hygienist (ACGIH) Threshold Limit Value (10 ppm) as well as the industrial guideline of 25 ppm published by the EPA in their proposed rulemaking to accept nPB under the Clean Air Act. Isopropyl bromide was not detected in either the air or breath samples. Exhaled breath concentrations of n-propyl bromide ranged from ND to 0.13 ppm and ND to 0.38 ppm, respectively, for pre-shift samples and post-shift samples. Average urinary bromide concentrations were approximately 77% higher for workers than for unexposed control subjects who were not employed by the company. Twenty-four hour average propyl mercapturic acid concentrations measured in urine specimens from workers were over an order of magnitude higher than that measured in control samples. Dermal absorption may have contributed to some of the workers' exposure in addition to inhalation exposure. Workers with the lowest breathing zone concentrations of nPB had urinary metabolite levels similar to those measured in control specimens. At this time, the health significance of these levels of urinary metabolites is unclear. Recommendations include, but are not limited to, substitution of nPB solvents with a less toxic solvent (if feasible), periodic exposure monitoring, use of gloves that are impermeable to nPB, and routine medical examinations.
Aerospace-industry; Solvent-vapor-degreasing; Solvents; Air-quality-measurement; Breathing-zone; Urinalysis; Region-5
National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations and Field Studies, Industrywide Studies Branch, 4676 Columbia Parkway, Cincinnati, OH 45226
106-94-5; 75-26-3; 7726-95-6
Field Studies; Industry Wide
NTIS Accession No.
National Institute for Occupational Safety and Health