GENTECH archive 8.96-97


PANUPS: Tolerance for Bromoxynil

                         P A N U P S
                   Pesticide Action Network 
                        North America
                       Updates Service
December 17, 1997
Urge EPA to Deny Tolerance for Bromoxynil on Genetically 
Engineered Cotton
The U.S. Environmental Protection Agency (EPA) is once again 
in the process of deciding whether to renew a tolerance for 
bromoxynil on cotton genetically engineered to be resistant 
to the herbicide. The Union of Concerned Scientists (UCS) is 
asking EPA to deny renewal of the tolerance for bromoxynil.
Several months ago, UCS issued a similar action alert asking 
individuals and groups to write to the U.S. Environmental 
Protection Agency (EPA) to urge the Agency to deny a 
tolerance for bromoxynil on cotton. EPA, however, approved a 
six-month tolerance for bromoxynil on cotton at that time. 
Now that tolerance is again up for renewal. 
In 1995, EPA approved a conditional registration for use of 
bromoxynil on transgenic bromoxynil-tolerant cotton. The crop 
was grown commercially in 1995 and 1996 under this 
registration. EPA also established a temporary tolerance -- a 
maximum permissible limit for the residues of bromoxynil in 
or on cottonseed -- which expired April 1, 1997. 
In June 1997, EPA approved six-month tolerances for 
bromoxynil and its metabolite DBHA (3,5-dibromo-4- 
hydrobenzoic acid) in or on cottonseed, undelinted 
cottonseed, cotton gin by-products, and cotton hulls. The 
Agency also established or revised tolerances for bromoxynil 
in eggs, poultry and other meat, meat by-products and fat.
On November 26, 1997, EPA announced that Rhone-Poulenc, 
manufacturer of the herbicide, had filed a petition for a 
one-year extension of tolerances for bromoxynil and DBHA in 
undelinted cottonseed, cotton gin byproducts, and cotton 
hulls; and for an increase from 3% to 10% (1.3 million acres) 
of the U.S. cotton acreage to which bromoxynil could be 
applied. The Agency granted a 30-day period for the public to 
comment on the petition. A decision will be made after 
December 26, and no further public comment will be allowed.
UCS is asking that you write to EPA and tell them to deny 
Rhone-Poulenc's request for a one-year extension of 
bromoxynil and DBHA tolerances: 
1) Bromoxynil is a toxic chemical with numerous known adverse 
health and environmental effects.
EPA has classified bromoxynil as a possible human carcinogen 
because it causes liver cancer in mice. The herbicide is 
known to be a developmental toxicant as it causes birth 
defects in mammals. Bromoxynil is also highly toxic to 
broadleaf plants and fish and thereby poses environmental 
threats. These data alone are sufficient to allow EPA to deny 
a tolerance.
2) The carcinogenic risk of bromoxynil exceeds the one-in-a- 
million standard of the Food Quality Protection Act. 
The Food Quality Protection Act (FQPA) requires EPA to 
implement a new safety standard -- a "reasonable certainty of 
no harm" for aggregate exposure using dietary residues and all 
other reliable exposure information. The legislative history 
of the FQPA establishes the reasonable-certainty-of- no-harm 
standard for nonthreshold (cancer) effects at a one- 
in-a-million risk level, meaning one additional cancer for 
each one million people exposed. EPA's estimate of the 
carcinogenic risk of bromoxynil in food sources and drinking 
water -- 2.1 in a million -- exceeds the one-in-a-million risk 
3) The Agency lacks sufficient safety data to set tolerances 
for DBHA, the metabolite produced by genetically engineered 
Bromoxynil-tolerant cotton is able to withstand bromoxynil 
because it contains an enzyme that breaks the herbicide down 
into a metabolite -- DBHA. The Agency knows that DBHA 
accounts for nearly 80% of the residues found in cotton after 
bromoxynil application. It expects DBHA residues will be 
found in cottonseed oil and meal and in beef, pork, poultry, 
and eggs from animals that consume the meal. Though the 
Agency and Rhone-Poulenc have known about DBHA for years, the 
company has submitted only preliminary data on its toxicity. 
EPA has not required DBHA safety data as a condition of 
Last spring, the Agency set tolerances for the first time for 
the metabolite. Absent data, the Agency relied on the 
assumption that DBHA is "toxicologically equal" to the parent 
bromoxynil, that is, a carcinogen with the same potency as 
bromoxynil. But DBHA may be more potent than bromoxynil or may 
act as an endocrine disrupter as well as a carcinogen. The 
Agency established tolerances without answering these 
questions. It appears from the current petition that Rhone- 
Poulenc still has not supplied adequate safety data on DBHA.
The Union of Concerned Scientists feels that given the lack 
of data on DBHA, the failure to comply with the FQPA, and 
bromoxynil's record on birth defects, the Agency should not 
renew tolerances for bromoxynil or DBHA on transgenic cotton. 
Send comments to arrive on or before December 26, 1997, to:
Docket Control Number PF-779
Public Information and Records Integrity Branch 
Information Resources and Services Division (7502C) 
EPA/Office of Pesticide Programs
401 M St., SW, Washington, DC 20460; or 
fax: (703) 305-4646; or
(submit as ASCII file and do not use special characters or 
Food Quality Protection Act, section 408(b)(2)(A)(ii), 1996. 
Environmental Working Group and Natural Resources Defense 
Council, "Fact sheet: the impact of the new pesticide law," 
Washington, DC.
EPA, "PP#3F04233. Extension of conditional registration for 
the use of bromoxynil on transgenic cotton," Memo from R. 
Griffin et al. to D. Stubbs, Office of Pesticide Programs, 
April 8, 1997. 
EPA, "PP#3F04233. Assumptions for estimating bromoxynil 
exposure from drinking water," Memo from R. Griffin to D. 
Stubbs, Office of Pesticide Programs, May 6, 1997.
EPA, November 26, 1997. "Notice of filing of pesticide 
petition." Federal Register 62:63170-74.
Contact: Jane Rissler, Ph.D., Union of Concerned Scientists, 
1616 P Street NW, Suite 310, Washington DC 20036; phone (202) 
332-0900; fax (202) 332-0905; email
Pesticide Action Network North America (PANNA) 
116 New Montgomery, #810, San Francisco, CA 94105 
Phone:(415) 541-9140
Fax:(415) 541-9253
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