Thursday, August 21, 1997

Methyl Bromide Poisoning

State's Internal Study Showed Danger of Drifting Fumigant One Year Before Victim Died of Methyl Bromide Poisoning


  • David Chatfield, Californians for Pesticide Reform: (415) 561-6598
  • Bill Walker, Environmental Working Group: (415) 561-6598

On March 20, 1996, eight days after Gov. Pete Wilson signed a bill overturning the state ban on methyl bromide, the California Department of Pesticide Regulation (DPR) published an internal report showing that when the poison gas is used to fumigate homes, unsafe levels of hazardous vapors can drift through empty pipes into neighboring houses. The study also found that methyl bromide levels outside homes under fumigation can be more than seven times higher than the state safety standard, and that methyl bromide can be detected inside closed houses up to 100 feet away from the fumigated structure, even if the two buildings are not connected by pipes of any kind (DPR 1996a, 1996b).

The study, conducted at the same time that Legislature was debating the overturn of the ban, constituted explosive but unpublicized evidence to support arguments against methyl bromide's continued use in structural fumigation. In 1995, almost 600,000 pounds of methyl bromide was used to fumigate thousands of California homes and businesses (DPR 1995). In Los Angeles and Orange counties alone, more than 500,000 pounds of methyl bromide was used that year, enough to fumigate 8,400 single-family homes (Table 1). But DPR made no effort to publicize the study or warn lawmakers, local authorities or fumigators of the threat to public health.

Table 1. Methyl Bromide applied in structural fumigations in California in 1995. (All counties with 1,000 pounds or more.)

County Methyl
Bromide (lbs.)
Home Fumigation capacity*
Los Angeles 389,346 6,489
Orange 114,320 1,905
Riverside 13,990 233
Sacramento 9,504 158
San Bernardino 9,060 151
San Joaquin 7,792 130
Sonoma 7,696 128
San Mateo 5,231 87
Marin 5,148 86
Monterey 4,645 77
Alameda 4,610 77
Santa Cruz 3,196 53
Stanislaus 3,083 51
San Diego 2,294 38
Contra Costa 2,075 35
San Luis Obispo 1,739 29
Napa 1,458 24
Fresno 1,210 20
Mendocino 1,145 19
Placer 1,101 18
Solano 1,094 18
STATEWIDE 598,656 9,978

Source: Californians for Pesticide Reform/Environmental Working Group, from California Department of Pesticide Regulation, Pesticide Use Reporting System.

*Estimate based on 2,500 sq. ft. house fumigated with 3 lbs. per 1,000 cu. ft. of methyl bromide as described in DPR HS-1717.

Almost exactly one year later -- March 25, 1997 -- Sandra Mero, 36, died in a Burbank hospital. She had fallen into a coma after a building near her house was fumigated with methyl bromide and the chemical drifted through empty pipes connecting the building to her home. Mero's doctor told the victim's family that blood tests found evidence of methyl bromide well above lethal levels (Berry 1997). Mero was the 19th person to die in California from methyl bromide poisoning since 1984 -- the same year the original law was passed to phase out the chemical.

In an interview two days before Mero died, DPR Director James Wells acknowledged that methyl bromide is "acutely toxic," adding: "That's why we're so careful about how we control its use" (Bernstein 1997). But an investigation by Environmental Working Group and Californians for Pesticide Reform found no evidence DPR tightened controls on structural fumigation with methyl bromide after the1996 study, or since Mero's death.

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