REGULATORY OVERVIEW OF METHYL BROMIDE AS A FUMIGANT IN THE UNITED STATES OF AMERICA

Since July, 1981, United States Environmental Protection Agency (EPA) has initiated four data call-ins on methyl bromide under the Federal Insecticide, Fungicide and Rodenticide Act. The data obtained under these data call-ins allowed EPA to review and assess the pesticide with the ultimate issuance of a registration standard. The standard then became EPA's criterion for reregistering products containing methyl bromide.

A registration standard for methyl bromide was issued in August, 1986. Under this standard, registrants were required to generate additional oral chronic data, residue data (both for methyl bromide per se and inorganic bromide), teratology data, plant metabolism data and product chemistry. There were extensive label revisions and the development of a required applications manual which detailed the safe uses of methyl bromide.

Methyl bromide is classified as a restricted pesticide in the United States. The product can be applied only by certified applicators or persons under their direct supervision. During fumigation, two persons must be present unless fumigation is done remotely. In addition, self-contained breathing apparatus is required if methyl bromide concentration exceeds 5 ppm (20 mg/m³). Placarding is required in all fumigated areas to avoid inadvertent exposure. Soil and non-raw agricultural commodity fumigations must be done with methyl bromide containing chloropicrin as a warning agent.

EPA requested oral chronic toxicity data to support the post-harvest commodity fumigation use. However, due to the toxicity of methyl bromide, EPA has agreed to a pharmacokinetic study to compare the methyl bromide blood level via oral and inhalation routes of exposure. Should the blood levels be comparable, EPA would consider a waiver on the two required oncogenicity studies by gavage.

In addition to EPA requirements, several states such as California, Florida and Arizona have enacted legislation requiring data for the continued use of methyl bromide in their state.