Occupational asthma in a factory making flux-cored solder containing colophony.

Abstract

The prevalence of work-related wheeze and breathlessness was measured in factory employees manufacturing flux-cored solder. The flux contained colophony which was heated in the production process, exposing the workers to colophony fumes. Measurement of colophony in the breathing zone defined three grades of exposure with median levels of 1-92 mg/i3 (six subjects), 0-02 mg/m3 (14 subjects), and less than 0O01 mg/m3 (68 subjects). All but two workers in the first two groups, and 90 % of a random sample of the last group, were studied. Occupational asthma was present in 21 % of the higher two exposure groups and 40% of the lowest exposure group. Mean values of FEV1 and FVC fell with increasing exposure. The prevalence of upper and lower respiratory symptoms was only one-third to a half that found in a previous study of shop floor electronics workers, whose work raised the flux to a higher temperature and produced higher concentrations of colophony fume. Total IgM levels were higher in the solder manufacturers than in unexposed controls, and were higher still in the electronics workers. The solder manufacturers were exposed to colophony fumes at 140°C, below the temperature at which the resin acids decompose, supporting the hypothesis that it is the whole resin acids rather than decomposition products which cause occupational asthma. The threshold limit value should be based on the resin acid content of the fume, and not the aldehyde content as at present. The survey suggests that sensitisation will not be prevented unless exposure is kept well below the present threshold limit value.Colophony (rosin, pine resin), the principal constituent of non-corrosive soft soldering fluxes, has been shown to be the sensitising agent in a group of electronics workers with occupational asthma.'-3 A prevalence study of respiratory symptoms in a factory making consumer electronics by mass production techniques showed that 22% of the shop floor workforce had work-related wheeze or breathlessness or both. It was thought that the level and duration of exposure to fume were the most important factors leading to sensitisation.5 6 Resin acids are broken down on heating above 200°C to form a large number of compounds, some of which are aldehydes,7 so the composition of the fume depends on the temperature at which it is heated.8 Bronchial provocation studies have shown that reactions to colophony in sensitised workers are reduced by methylation of the resin acid carboxyl groups. The whole resin acids are likely to be the cause of the asthma as the thermal degradation products should be similar with methylated and unmodified resin acids. The factory processWe were asked to investigate workers in a factory making flux-cored solder containing American WW and Portuguese Y colophonies (in future called solder manufacturers) to investigate the effects of colophony fumes produced by heating at a temperature lower than the 350-450°C common in electronics factories. The factory was in two separated buildings. Four men were employed in a sm...

Aetiological agents in occupational asthma

“…A man aged 50 yrs developed obstructive airways disease after exposure to high concentration of ammonia vapours [136]. Several other studies of the sequelae of chlorine gas exposure showed similar findings [137,138].…”

Abietic acid [MAK Value Documentation, 2013]

“…Restrictions in lung function and obstructive respiratory diseases have been described especially after longer term exposure to abietic acid or its oxidation and decomposition products in vapours of soldering fluxes containing rosin (see also documentation "Rosin (colophony)" 1998, supplement "Rosin" 2013; Burge 1982Burge , 1984Burge et al 1980Burge et al , 1981Palmer and Crane 1997;Pengelly et al 1998 b) or during the manufacture of soldering fluxes containing rosin (temperature >140°1 C) (Burge et al 1981). Such symptoms also occurred after exposure to vapours of hot-melt adhesives based on rosin (Fawcett et al 1976;, unheated rosin dust (Burge et al 1986), heated rubber chemicals (Tarlo 1992), pinewood dust containing abietic and pimaric acid (Ayars et al 1989;Teschke et al 1999;Whitehead et al 1981), aerosols of aw ater-miscible coolant (Hendy et al 1985) or cleaning agents containing rosin (McCoach et al 1999).…”

New occupational allergen in citrus farmers: citrus red mite (Panonychus citri)

“…The duration of latency seems to depend on the nature of the causal agent, and exposure duration and intensity to a sensitizing agent. [15][16][17][18][19][20] In subjects with occupational asthma caused by high molecular weight agents, the latent period was longer than in those caused by low molecular weight agents. In the latter instance, 50% of patients develop symptoms within the first 2 years of exposure.…”