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California Environmental Protection Agency

Department of Pesticide Regulation


Release No. 95-04
Date: February 2, 1995

DPR TO CANCEL THE REGISTRATION OF MEVINPHOS

SACRAMENTO -- Cal/EPA's Department of Pesticide Regulation today initiated legal action to cancel the registration of all products containing the insecticide, mevinphos, with the effective date to coincide with a federally imposed phaseout.

DPR expects that all required activities leading to cancellation will be completed and the cancellation final by November 30, 1995, the date mevinphos use is scheduled to end nationally under an agreement signed last month between the U.S. Environmental Protection Agency and Amvac, the Los Angeles-based manufacturer of mevinphos.

"We have no reason to believe that use will not end on November 30 as scheduled," said James W. Wells, DPR Director. "However, by taking this action, we ensure that in California, use will stop on November 30. Meanwhile, strict mevinphos restrictions in this state ensure that only critical uses will be allowed up to that date."

In June 1994, under the threat of impending cancellation actions by USEPA and DPR, Amvac agreed to voluntarily end production and cancel the registration of all uses. Under its agreement with USEPA, sales by dealers were to end in December 1994 and all use on February 28, 1995. Last month, USEPA and Amvac revised their agreement, extending until November 30, 1995 the time frame for sale, distribution, and use of this pesticide. After November 30, Amvac is required to recall all products, including opened containers. The company will provide reimbursement for all unopened containers, down to the end-user level.

In a statement, USEPA said it was extending the time frame for two major reasons:

Amvac agreed to a plan that for the first time obligates a company to recall its products not only from dealers and distributors but also from end users. (A mandatory recall would have only obligated Amvac to recall from distributors and dealers, not end users.) Included in the recall will be partially used containers. Disposal of partially used containers has been a problem in some past cancellation actions and has been expensive to states.

While Amvac has not been allowed to produce any mevinphos since July 1, 1994, existing stocks have not been used as quickly as expected. USEPA expressed concern about the hazards of long-term storage or disposal of large quantities of mevinphos products as a hazardous waste.

Mevinphos, also known by the trade name, Phosdrin, is a broad-spectrum organophosphate insecticide. It is used to control aphids, leaf miners, mites, grasshoppers, caterpillars, and many other insects. Mevinphos is used only in production agriculture.

Because of its acute toxicity, mevinphos has been a restricted-use pesticide for many years. Restricted-use products may be possessed and used only by state- and county-certified persons who have shown they can safely use and handle the product and who have obtained a permit for use from the county agricultural commissioner.

In June, when the voluntary cancellation was announced, DPR and the county agricultural commissioners imposed strict use conditions on mevinphos use. Included was a ban on use on grapes and tree fruit, and in greenhouses; a 1/2-mile buffer zone between aerial applications and fieldworkers; and a ban on the use of hand-held application equipment and air-blast sprayers.

"Our intention was to impose additional safety measures beyond the highly restrictive use requirements already in place," said Wells. "These precautionary measures were designed to provide added protection to workers and in this we succeeded. From 1990 through 1993, we had an annual average of 54 worker illnesses associated with mevinphos exposure. In 1994, from July through December with the new use practices in effect, only two potential illnesses occurred, according to our preliminary reports."

Wells added that since June 1994, use of mevinphos declined significantly--about 65 to 70 percent compared to previous years. "Not only did the use restrictions have an effect, but there may have been reduced pest pressure," he said.

Total reported mevinphos use in California in 1992 was 228,290 pounds, 294,441 pounds in 1991, and 333,793 pounds in 1990. During these three years, more than 60 percent was used on head and leaf lettuce and broccoli.

With the phaseout extended until November, DPR has reexamined the permit conditions imposed last year, Wells said. "Since the restrictions will be in effect through another growing season, we wanted to see if they needed any fine-tuning," said Wells. "Most of the restrictions are working well and are protective. A few need to be modified."

Since 65 percent of historical mevinphos-related illnesses were a result of drift, no changes will be made in the buffer zones for aerial applications. "We also wanted to keep the ban on use on grapes and other crops with high worker contact with foliage," said Wells.

"However, one change we are making is that the use of mevinphos in tank mixes may be allowed if absolutely necessary," Wells said.

The 1994 permit conditions had prohibited combining mevinphos in application tanks with other cholinesterase-inhibiting pesticides. "The idea was to eliminate unnecessary applications We didn't want mevinphos added to a tank mix as an extra--but unneeded--layer of protection. But instead there is some evidence that growers who really needed to use mevinphos were sending applicators through a field twice--once with the tank mix minus mevinphos, and then with mevinphos alone. A worker making two applications is at greater risk than if he makes one. Therefore, we have decided to allow mevinphos in tank mixes, but only if a licensed pest control adviser provides written justification of the need to use mevinphos at all."

Under the revised permit conditions, the role of pest control advisers (PCAs) has been greatly expanded, Wells said. "Before a grower can apply mevinphos, a PCA must file with the county agricultural commissioner a written recommendation that describes the pest problem in detail and provides an explanation of why other chemicals are not feasible for the specific pest situation.

"Mevinphos should be used only in situations where no other alternative exists," said Wells.

In 1994, mevinphos could only be used from two to 14 days before harvest, as a final "clean-up" application. "We found that the most critical time for application may not be just before harvest," said Wells. "With an expanded role for PCAs in ensuring that only critical uses of mevinphos are approved, mevinphos can now be used any time during the growing season."