Washington, DC
April 27, 2005
EPA’s Regulatory Process
and Evaluation of Bt10
The United States Environmental Protection Agency regulates
pesticidal substances produced in plants and the genetic
material necessary for the plant to make those substances. Under
the Federal Insecticide, Fungicide, and Rodenticide Act, a
compound is a pesticide if there is a claim that the substance
will control a pest such as an insect, weed, or plant pathogen.
EPA calls these pesticidal substances plant-incorporated
protectants when they are intended to be used in the plant. EPA
does not regulate such products when they are produced through
conventional breeding techniques, but is regulating new
substances such as those produced through modern biotechnology.
EPA also must make a determination about the safety of any
pesticide residues in food or feed as required under the Federal
Food, Drug, and Cosmetic Act (FFDCA). EPA’s authority is only
with pesticides and the U.S. Food and Drug Administration has
authority for other provisions of FFDCA.
In order to be sold legally as
food or feed in the United States, crops containing
plant-incorporated protectants, such as the Bacillus
thuringiensis (Bt) Cry1Ab protein produced by Bt10, must be
covered by a tolerance or an exemption from tolerance issued by
EPA under its FFDCA authority after completion of its safety
review and a rule making process which allows for public comment
and EPA to respond to any comments.
EPA granted an exemption from
tolerance for Bt Cry1Ab protein in all food and feed commodities
on August 2, 1996. The tolerance exemption is published in the
Code of Federal Regulations (40CFR 180.1173) . In September
2001, EPA completed a reassessment of this tolerance exemption
considering all of the existing data, public literature, and
public comments. The reassessment determined that the tolerance
exemption met all the scientific and regulatory standards. This
tolerance exemption for the Bt Cry1Ab protein is not
event-specific and therefore applies to all Cry1Ab protein
including Bt10, Bt11, MON810, Event 176 and any other event
producing the Cry1Ab protein that might be found in the food
supply.
EPA's Risk Assessment
for Bt10 Plant-Incorporated Protectants
Syngenta performed the DNA
sequence analysis of the genetic insert of the Bt10 event and
submitted the sequence to the Agency. The coding sequences of
the Bt10 event are identical to those previously reported for
the registered event, Bt11. Syngenta provided data that all of
the nucleotides in the coding region are identical in Bt10 and
Bt11. The expressed proteins are Cry1Ab and the inert marker PAT
for herbicide tolerance. Syngenta also performed western blot
analysis on the proteins expressed in leaf tissue from the Bt 10
event. The Cry1Ab and PAT proteins extracted from leaf tissue
from the Bt10 event appear to be the same as the proteins from
leaf tissue from Bt11 event based on the immunoreactivity of
comigrating bands. Syngenta submitted a published article
comparing the Cry1Ab expression level in corn from event Bt10
compared with event Bt11, which showed that a hybrid produced
from event Bt10 has much lower expression levels of Cry1Ab (< 1
ng/mg soluble protein) than hybrids produced from event Bt11
(257-457 ng/mg soluble protein). Lower expression levels of the
Cry1Ab protein mean there is even a lower potential for possible
adverse environmental effects on animals, birds, fish, and
non-target insects.
Bt10 also has a marker gene for
resistance to the antibiotic ampicillin which is not present in
Bt11. The gene is under the control of a bacterial promoter and
is not expected to be expressed in the corn so it does not need
to be covered by any tolerance or tolerance exemption. According
to information provided by Syngenta, the antibiotic resistance
marker gene in Bt10 is the same as that in Event 176 corn.
40CFR 180.1173 - Bacillus
thuringiensis CryIA(b) delta-endotoxin and the genetic material
necessary for its production in all plants.
Bacillus thuringiensis CryIA(b) delta-endotoxin and the genetic
material necessary for its production in all plants are exempt
from the requirement of a tolerance when used as plant
pesticides in all plant raw agricultural commodities. “Genetic
material necessary for its production” means the genetic
material which comprise genetic material encoding the CryIA(b)
delta-endotoxin and its regulatory regions. “Regulatory regions”
are the genetic material that control the expression of the
genetic material encoding the CryIA(b) delta-endotoxin, such as
promoters, terminators, and enhancers. [61
FR 40343, Aug. 2, 1996]
40CFR 180.1151 - Phosphinothricin acetyltransferase (PAT) and
the genetic material necessary for its production all plants;
exemption from the requirement of a tolerance.
Phosphinothricin acetyltransferase (PAT) and the genetic
material necessary for its production in all plants are exempt
from the requirement of a tolerance when used as plant-pesticide
inert ingredients in all plant raw agricultural commodities.
“Genetic material necessary for its production” means the
genetic material which comprise genetic material encoding the
PAT protein and its regulatory regions. “Regulatory regions” are
the genetic material that control the expression of the genetic
material encoding the PAT protein, such as promoters,
terminators, and enhancers. [62
FR 17719, Apr. 11, 1997]
For more information on FDA’s
position on Bt10, see
U. S. Food
and Drug Administration’s Statement on Bt10.
For more information on the
respective roles of USDA-APHIS, EPA, and FDA in the federal
regulation of genetically engineered plants, see the United
States Agencies Unified Biotechnology Website at
http://usbiotechreg.nbii.gov/. |