In 1994, a team of scientists locked dozens of dogs in airtight plastic boxes and then pumped the pesticide methyl bromide into these containers for seven hours each day for a month.
The devastating effects were noted in a brief, dispassionate summary of their experiment.
“Bodyweight loss and neurotoxicity were seen in the dogs exposed,” wrote scientist Paul Newton, who led the study for the research firm Pharmaco SLR in New Jersey. “Three…dogs had to be sacrificed due to exhibiting oposthotonos [painful spasm in which spine and neck arch backwards], irregular gait, opening and closing of the jaws and convulsions.”
Other dogs exposed displayed eyeball spasms, severe shaking, loss of coordination, diminished responsiveness, weight loss and depression.
The dog experiment confirmed what scientists already suspected: methyl bromide is an extremely dangerous pesticide. In 2002, state scientists used the results of the experiment to approve acceptable exposure levels of methyl bromide for humans. They did so even though the experiment failed to measure potential long-term neurological effects from methyl bromide exposure.
Now, the state is fighting to maintain revised methyl bromide rules that allow farm-workers and residents near ag fields to be exposed to higher amounts of the pesticide.
Methyl bromide remains one of the most widely used agriculture pesticides in the state. In Monterey County in 2004, farmers pumped almost 1.3 million pounds of methyl bromide into the soil, mostly on strawberry fields, making it the second-most-used pesticide in the county after sulfur. Methyl bromide was supposed to have been banned in the US by 2005 under an international accord, but its use in California spiked from 2002 to 2004 by more than half a million pounds (from 6.5 million pounds to 7.1 million pounds).
To date, however, no study has comprehensively measured the long-term neurological effects of methyl bromide on humans. Little is known about methyl bromide’s effects on people who’ve been exposed to small quantities over a period of about three months (called subchronic exposure). Despite this, in 2004 the state Department of Pesticide Regulation (DPR) watered down existing methyl bromide exposure levels for humans.
Strawberry farmers, who rely on the ozone-depleting poison to fumigate their fields, have long lobbied DPR to ease methyl bromide regulations.
The revised rules raised methyl bromide exposure levels for humans by 900 percent. DPR officials based the looser regulations on a second methyl bromide dog study that, like the one done in 1994, also did not address outstanding questions about methyl bromide’s potential long-term effects on humans.
In response to the new, looser regulations, several groups, including California Rural Legal Assistance (CRLA) in Salinas, sued DPR, arguing that its scientists willfully and illegally ignored other state scientists who favored stricter rules.
In December of last year, a Superior Court judge in San Francisco sided with CRLA and others. The judge gave DPR one year to rewrite methyl bromide subchronic exposure levels to coincide with the state’s Office of Environmental Health Hazard Assessment.
Last month, however, Gov. Arnold Schwarzenegger and DPR appealed the court ruling. By appealing, DPR has essentially handed strawberry farmers who use methyl bromide at least one more year—and perhaps two—to expose farmworkers and residents to higher quantities of methyl bromide than originally allowed under the 2002 exposure regulations.
This isn’t sitting well with environmental groups.
“The state is fighting pesticide protections for people,” says Linda Crop, chief counsel for Environmental Defense Center, which filed suit against DPR along with CRLA. “Instead of agreeing to protect the public, DPR has shown its true colors in siding with the chemical industry.”
DPR spokesman Glenn Brank confirmed that DPR last month appealed the December ruling, but added that no further comments on the issue would be forthcoming for several weeks.
Susan Kegley, a senior scientist with Pesticide Action Network of North America, says she can’t understand why DPR officials originally loosened the methyl bromide rules in 2004. “If DPR is thinking about protecting human health, you’d think they would have chosen the more conservative numbers,” Kegley says. “They’re essentially using human beings as guinea pigs.”
While methyl bromide was supposed to have been phased out in 2005, state agencies like DPR have successfully applied for yearly exemptions that allow farmers to continue using methyl bromide in California.
Last month, after intense public pressure, DPR pulled back on authorizing a replacement pesticide for methyl bromide, methyl iodide, which is even more toxic than methyl bromide.