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bromoxynil (Brominal, Buctril) EPA Risk Reduction Measures Imposed 5/89

SUBJECT: Press release on Bromoxynil -- 5/9/89
TO: State Extension Pesticide Coordinators FOR RELEASE: TUESDAY, MAY 9, 1989
Al Heier (202) 382-4374
The U.S. Environmental Protection Agency today imposed substantial risk-
reduction measures on the use of the pesticide bromoxynil including requiring 
a warning label that it causes birth defects in laboratory animals, 
restricting its use to certified applicators and requiring protective clothing 
for mixers, loaders and applicators.
The pesticide registrant has agreed to conduct an extensive program to inform 
bromoxynil users about the potential birth-defect risks for mixers, loaders 
and applicators and the importance of following the new risk-reduction 
measures. The registrant is also providing extensive data to enable the agency 
to estimate better the magnitude of risk to exposed workers.
EPA has determined that the risk from dietary exposure is negligible. Residue 
levels are not detectible on the food crops, including small grains, field 
corn, garlic and onions, on which bromoxynil (trade name Buctril) is used to 
control broadleaf weeds. It is not registered for homeowner use.
The agency's warning is based primarily on a recent study which shows that 
bromoxynil causes birth defects in the offspring of pregnant rats exposed to 
it through skin contact. Oral studies in which bromoxynil was administered 
showed similar developmental effects.
"We are requiring that numerous new protective measures be added to the label 
directions on all bromoxynil products within the next few weeks to provide 
adequate safeguards this growing season for workers mixing, loading and 
applying this pesticide," said Victor Kimm, EPA's Acting Assistant 
Administrator for Pesticides and Toxic Substances.
Rhone-Poulenc Agricultural Co., the sole registrant for bromoxynil, agreed on 
April 26 that it would immediately withdraw all bromoxynil butyrate products 
from the market because of the higher skin absorbant rate compared to other 
bromoxynil formulations and will relabel all remaining bromoxynil products 
(bromoxynil octanoate) at the distributor level within the next three weeks. 
The remaining octanoate products will no longer be registered for use on turf 
and non-crop sites.
The new label directions include:
- restricting use to certified applicators;
- a warning that exposure during pregnancy causes birth defects in laboratory 
animals;
- a requirement that mixers, loaders and applicators wear coveralls over a 
long-sleeved shirt and long pants and chemical-resistant shoes or boots;
- requiring that mixers and loaders also wear a chemical-resistant apron and 
goggles or face shield if using open-pour systems;
- requiring clean nitrile gloves for all operations and that they be rinsed 
before removal and between operations and discarded after one days's use;
- allowing only mechanical flaggers for aerial operations;
- requiring that applications of 180 acres or more per day by a single 
operator be done using an enclosed cab or aerially;
- and, a requirement that application of more than 30 gallons be done using a 
mechanical transfer system.
The California Department of Food and Agriculture imposed similar label 
amendments on bromoxynil products in December 1988. Canada has also recently 
required protective measures for persons handling bromoxynil products.
EPA believes that compliance with the new label directions and restrictions 
will provide adequate protection from the risk of birth defects. The exposure 
and toxicity information currently available at the agency, however, is not 
sufficient to enable quantification of the degree of protection provided by 
these risk-reduction measures. In order to assure that these protection 
measures are sufficient, EPA has made the continued registration of bromoxynil 
conditional upon Rhone-Poulenc's developing new toxicity and extensive 
exposure data by the end of 1990 which will be reviewed prior to the 1991 
growing season.
The registrant also agreed to accelerate the development of containers to 
reduce worker exposure during mixing and loading,
including a commitment to use hard coupling on bulk containers (to enable a 
closed system transfer) for the 1990 growing season. EPA has been urging the 
development of such pesticide packaging which together with returnable 
containers can greatly reduce worker exposure to all pesticide products in the 
future.
Most of the studies done on bromoxynil were conducted with bromoxynil phenol, 
whereas bromoxynil octanoate is the product primarily being marketed. The rat 
dermal study using bromoxynil phenol which was recently submitted to the 
agency and served as the primary basis for the label modificaitons will be 
compared to a similar study on bromoxynil octanoate which is due to the agency 
at the end of May.
Bromoxynil has been registered since 1965. According to 1988 estimates, 
approximately 8 percent of the field corn in the United States is treated with 
bromoxynil, 6 percent of the small grains
including wheat, 50 percent of the onions, 95 percent of the garlic, five 
percent of the flax, 30 percent of the mint and up to 100 percent of the 
canary grass. Approximately 2.2 million pounds are used annually.
The two butyrate products which the registrant has voluntarily cancelled and 
will recall for disposal are identified as EPA Reg. No. 264-340 ad marketed as 
ME 4 Brominal, Buctril ME 4. Torch Twin Pak, and 3 + 3 Brominal; and EPA Reg. 
No. 264-421 marketed as Certrol. The following products were also voluntarily 
cancelled and should no longer be found in the channels of trade: Nulawn 
Weeder 264-250), Brominal Plus (264-239), FL 2 Brominal (264-408), Bromoxynil 
Butyrate Technical (264-394), Mallet PM Bromoxynil Atrazine (264-434), Chipco 
Buctril (264-446), Buctril Industrial (264-448), Buctril 4EC (264-474) and 
Brominal (264-204).