A Cross-Sectional Survey of 32 Workers Exposed to Hexahydrophthalic and Methylhexahydrophthalic Anhydrides.

Abstract

Abstract:The relation between exposure and sensitization or the appearance of symptoms of the eyes and airways was investigated in a cross-sectional study on 32 workers from a plant using epoxy resin with a mixture of hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) as a hardener. The main component in the hardener was HHPA, and the geometric mean concentrations of HHPA in the workplaces were extremely low (<40 µg/m 3 ) in recent years, compared to the Occupational Exposure Limit-Ceiling for phthalic anhydride (2 mg/m 3 ). However, specific IgE antibody to HHPA was detected in serum from 8 (25%) out of the workers: of those, 5 workers experienced symptoms of the eyes and nose during work (group sensitized symptomatic (SS)) and 3 workers did not (group sensitized nonsymptomatic (SN)). The other 24 workers had no signs of sensitization and did not complain of work-related symptoms. Based on occupational history and anamnestic data, it was concluded that one subject in the SS group and all the subjects in the SN group had been sensitized by higher exposures in the past. The symptoms of 4 subjects in the SS group occurred only when carrying out short-time, particular tasks (15-30 min) a few times a day, such as the resin mixing procedures, manual application of the resin, or opening of ovens. High peak exposures were estimated to have occurred during the particular tasks. Our results suggest that short-time peak exposures may have a great impact on the development of specific IgE or work-related symptoms. Therefore, to minimize the risk of sensitization and work-related symptoms, a reduction of exposure during particular tasks with high peak exposures, along with a decrease in mean 8-h time-weighted average exposure, should be achieved.

Exposure to methylhexahydrophthalic anhydride (MHHPA) in two workplaces of the electric industry

“…MHHPA was the only hardener used in these two processes. In the earlier published studies, [9][10][11] the MHHPA concentration was lower with its share about 30-64% of the total anhydride concentration in the air. MHHPA had only been an additive ingredient for HHPA or MTHPA and its original concentration in the mixture was not informed.…”

“…With the exclusion of hexahydrophthalic anhydride (HHPA), the exposure-response data for sensitisation and other symptoms caused by the cyclic anhydrides are scanty, [9][10][11] due to the fact that the exposure concentrations causing health problems are known to be extremely low and insufficiently measured. MHHPA has only been measured as an additive ingredient in combination with HHPA or tetrahydrophthalic anhydride (THPA), and the methods employed for sampling and analysis have not been validated especially for MHHPA.…”

An evaluation of respiratory health at a syntactic foam manufacturing facility.

“…We know that many causes of allergic asthma exist in the facility. Exposure to epoxy resin systems containing ingredients such as amines, bisphenol A diglycidyl ether, and anhydrides including methyltetrahydrophthalic anhydride can cause allergic reactions (both immediate and delayed), dermatitis, and asthma [Fawcett et al 1977;Nielsen et al 1989;Kanerva et al 1991;Nielsen et al 1992;Patussi et al 1995;Yokota et al 1999;Nielsen et al 2001;Yokota et al 2002;Nielsen et al 2006;Hannu et al 2009;Helaskoski et al 2009;Malo and Chan-Yeung 2009;Foti et al 2010]. In addition to allergic sensitizers, workers may have been exposed to irritant causes of work-related asthma such as butanediol diglycidyl ether, aliphatic amines, anhydrides, bisphenol A, epichlorohydrin, and milled fibers.…”