OCCUPATIONAL AND PARAOCCUPATIONAL EXPOSURE TO METHYL BROMIDE DURING SOIL FUMIGATION IN SWITZERLAND

The use of methyl bromide (MB) as a fumigant in various fields of application in Switzerland was investigated in order to assess and prevent the risks of exposure to the applicators (occupational), to other workers (paraoccupational) and to the general population. The approach consisted in combining a formalized preliminary hazard analysis, conventional occupational hygiene field surveys using both direct reading measurements and integrated samples, and a MORT (Management Oversight and Risk Tree) risk analysis.

While only small amounts of MB are used for soil fumigation in Switzerland, a large number of persons without specific license or training are potentially involved. Recent trends tend however to limit this group. The techniques used are puncturable cans and hot vapor injection. One cold liquid injection application was also surveyed in France.

A major gap in present practices lies in the instruction to non-professional fumigators and paraoccupationally exposed personnel, including enforcement of existing working rules. More generally, MB illustrates a common situation in the horticultural and agricultural professions, where large amounts of potentially harmful products are used often without adequate knowledge of their hazardous properties and of appropriate preventive measures. The combined approach developed for this study provides a suitable framework for the assessment of risks in the use of other potentially toxic agents.