August 21, 1997

Methyl Bromide Poisoning: Double standard

This double standard means that Californians must be warned before methyl bromide is used in their homes, but not when it is applied to agricultural fields near their homes, schools or businesses. It also means that while the state's safety standard for exposure to methyl bromide from an agrigultural application is 210 parts per billion(ppb), averaged over 24 hours, the target safety level for exposure in a structural fumigation is 15.5 ppb. The practical effect is that Californians can legally be exposed to 13 times more methyl bromide on their back porches than in their living rooms.

But are the stricter Prop. 65 standards for structural fumigation adequate to protect the public? Between 1984 and 1996, 18 people died in California after entering fumigated homes. In 1992, a Redwood City man died even though post-fumigation tests showed "safe" levels of methyl bromide in his apartment. DPR found that the poison gas was "hiding" in the wall spaces and woodwork, only to seep out later in lethal amounts (DPR 1992..) Like Mero, he was in a coma for more than two weeks before dying.

To its credit, in 1992 DPR imposed new regulations that increased the waiting period before re-entering a fumigated house, lowered the acceptable level of methyl bromide allowed before re-entry and requred monitoring for methyl bromide lurking in wall spaces. Under the new restrictions, the use of methyl bromide in structural fumigation dropped dramatically -- from 5 million pounds in 1990 to 600,000 pounds in 1993.