Characterization of a fatal methyl bromide exposure by analysis of the water cooler.

Background A suspected inhalation exposure to methyl bromide (MeBr) in the packaging and shipping area of a chemical manufacturer resulted in a worker fatality and several symptomatic cases. However, air testing was negative for MeBr resulting in uncertainty regarding the potential chemical exposure. Methods of quickly confirming the exposure and magnitude were sought. Methods Head space air and water samples were obtained from the breakroom water cooler in the facility and tested for MeBr. Results Increased levels of MeBr were identified in the air and water samples from the cooler and used to calculate the MeBr concentration of air entering the cooler. The MeBr air concentration within the breakroom was estimated as 1,200–2,100 ppm depending on assumptions regarding the amount of water dispensed from the cooler both before and during the incident. Conclusions Estimated MeBr air concentrations in the breakroom were consistent with those known to be associated with reported health effects among the involved workers. The water cooler analysis represented a unique method of retrospectively verifying and quantifying exposure to MeBr. Am. J. Ind. Med. 52:579–586, 2009. © 2009 Wiley-Liss, Inc.