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
- 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
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
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