From the Director:
Why is California agriculture still using methyl bromide?
Ong Lee Yang (right) talks to Richard Molinar, Fresno County small farms advisor (center) and Michal Yang, UC Small Farm Program, about taking advantage of hot summers to tarp her fields as an alternative to methyl bromide.(UC photo by Jack Kelly Clark).
Methyl Bromide (MeBr) has been used as a fumigant to control arthropods, weeds, and diseases in diverse but specific sectors of agriculture for decades, and is very effective in this job. Unfortunately, MeBr is risky to farm workers, seems associated with prostate cancer and other illnesses, and depletes the stratospheric ozone layer. In the interests of full disclosure, I should mention that I lived under or neat the Antarctic “ozone hole” in South Australia for eight years, so I have something of a particular interest in this.
The amount of MeBr produced, imported, and used in the U.S. was supposed to be phased out on January 1, 2005, following the Montreal Protocol. However, there was a loophole for critical uses in which there are no alternatives available that are technically and economically feasible. For 2005, the Parties to the Protocol authorized 37 percent of the U.S. 1991 baseline for a critical use exemption. For 2007, the U.S. requested 29 percent of baseline, including exemptions for 15 crops or uses, such as tomatoes, strawberries, peppers, cucurbits, orchard replants, and post-harvest uses, much of this in Florida but also about half in California.
The USDA has a grant program, “Methyl Bromide Transitions,” to develop suitable alternatives to methyl bromide, currently funded at about $3 million per year. The program targets short- to medium-term solutions on a commercial or field scale. While this is aimed at more rapid replacement of MeBr, in practice this means there is a significant emphasis on alternative fumigants rather than more sustainable solutions. One potential alternative, methyl iodide, is moving through the registration process at US-EPA. Methyl iodide does not seem to be an ozone depleter, but still carries a number of health risks.
More than two years ago, University of California Agriculture and Natural Resources Vice President W.R. “Reg” Gomes wrote to the USDA about this concern. Noting that other fumigants contribute both to air pollution (as volatile organic compounds that add to ozone) and the majority of reported human illnesses from agricultural pesticide accidents across California over the last few years, Gomes noted that replacement of methyl bromide with other fumigants will simply trade one problem for another. Gomes urged that the USDA grant program be changed to encourage innovative alternatives to methyl bromide and other fumigants.
Perhaps even worse, at that time the USDA program allowed grants to develop “impact data that can be used to support Critical Use Exemptions for methyl bromide on specific crops.” That ambiguity, at least, has been dropped from the USDA program, but the emphasis is still on short- to mediumterm solutions, although some non-fumigant work and even non-chemical work is being supported, including among UC researchers.
The replacement of fumigants in agriculture is a huge job, but every small step will help. Consumers can help by being willing to pay extra for foods and flowers produced without fumigation and thereby provide incentives for fumigant-free agriculture.
UC SAREP will soon be issuing a call for proposals for research and extension on alternatives to methyl bromide and fumigation. We hope that we can help to bring more of the resources of the UC to bear on this problem. -Rick Roush, interim director, University of California Sustainable AgricultureResearch and Education Program
