A
REGULATORY STATUS OF 2-4-5T
REGION ix in 1972, when Congress amended the Federal pesticides law to
require stricter human health and environmental protection from pesticide
abuse, EPA was charged with issuing rules for reviewing all pesticides to
ensure they meet the new safety requirements. Some 35,000 pesticides consisting
of 1,400 basic ingredients are now sold in the U.S. A key part of the EPA
safety review is a process called "Rebuttable Presumption Against Registration"
or "RPAR". It has been in effect for two and one-half years.
EPA began the review of the risks and benefits of 2-4-5T for the
following reasons:
- The pesticide and its dioxin contaminant have killed fetuses or
caused birth defects, such as cleft palate, among laboratory mice, rats, hamsters
and birds in tests by the National Institutes of Health and other researchers.
- 2-4-5T and dioxin have caused leukemia or lung, liver or other
tumors among mice and rats in studies conducted by the National Institutes of
Health, Dow Chemical, and others.
i - EPA calculations show that "an ample margin of safety" may not
exist for persons applying the pesticide or people exposed to aircraft spraying it.
Many pesticide, agriculture and forestry officials argue, on the
other hand, that 2-4-5T is not a serious hazard, but the only effective, econ-
omical tool for controlling unwanted plant life. Under the RPAR process, users
of 2-4-5T must rebut the scientific evidence indicating a potential health hazard
fron the pesticide and present economic benefits.
EPA has been conducting ongoing studies on 2-4-5T, including:
analytical method validation to produce statistically defensible data; monitoring
for residues in human milk in the Pacific Northwest; analysis of beef fat residues
and technical pesticide residues; monitoring of soil, water and biota for residues.
Results of all studies, including the mothers' milk study, will be analyzed and
released by Spring, 1979, at which time EPA will decide whether the compound is
reasonably safe as used, whether additional limitations are needed, or whether
it should be removed fron the market. During this time, 2-4-5T may continue to
be sold.
RPAR is not the same as banning a pesticide. Whether this occurs
will depend upon the type of information received by EPA and a judgment^as to
whether benefits appear to outweigh risks or vice versa.
EPA's responsibility under the RPAR process is
to make sure that extensive scientific information about the
effects of 2-4-5T have been gathered before determining
whether prolonged, courtroom hearings on safety are necessary.
The Agency must insure that benefits and risks are given
full consideration.
October 2, 1978
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
215 Fremont Street San Francisco. Ca. 94105
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2,4,5-T FACT SHEET
Common Names: 2,4,5-T, Weedone, Esteron, Dacamine
Chemical Name: 2,4/5-Trichlorophenoxyacetic acid
Chemistry: 2,4,5-T is prepared from 2,4,5-Trichlorophenol
and monochloroacetic acid in aquenous Na OH. It is composed
of 37.61% carbon, 1.97% hydrogen, 41.63% chlorine, and 18.79%
oxygen having a molecular weight of 255.49.
Chemical Formula:
Molecular Structural^
„ »„, „ ew, c-on
C8H5Cl303 J~ 2.
CJ-
C4
Characteristics: 2,4,5-T is a crystalline solid almost
insoluble in water. It is soluble in alcohol and forms
water-soluble sodium and alkanolamine salts. The melting
point is 156.6°C.
Dioxin: During the first step in the manufacturing process
of 2,4,5-T, if temperature and pressure are not carefully
controlled, highly toxic contaminants, polychlorinated
dibenzo-p-dioxin, may be formed in large quantities. The
particular dioxin formed is dependent upon the chlorophenols
present. The term dioxin refers to a group of related
substances, each containing a distinguished number and
orientation of chlorine atoms. Dioxin toxicity also varies
with the position and numbers of chlorines attached to the
phenol rings.
In the 2,4,5-T manufacturing process a toxic dioxin,
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is formed when
the reaction temperature is excessive, most commonly at
temperatures above 160°C. This contaminant is of particular
concern due to its extremely high toxicity, and the manu-
facturers apparent inability to produce 2,4,5-T without
formation of TCDD.
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Forraulation and Class: 2,4,5-T is classed and used as a
selective herbicide, especially for brush control. It is
formulated in many forms of salts and esters which are
available as emulsifiable concentrates. They contain 2, 4,
or 6 pounds actual acid equivalent per gallon and as oil
soluble concentrates with 4 or 6 pounds active ingredient
(AI) per gallon. The most commonly used formulations are
the low volatile esters. 2,4,5-T also occurs in registrations
mixed with 2,4-D, Dicamba, Picloram, Silvex, and 2-(2-methyl-
4-chlorophenoxy) propionic acid.
Registrations: According to EPA records, approximately 122
companies hold Federal registrations and formulate 424 regis-
tered products; 11 companies have former state registrations
and formulate 21 products.
The principal manufacturers of 2,4,5-T are The Dow Chemical
Co., Transvaal Inc., Farbenfabriken Bayer, Thompson-Hayward
Chemical Co., and Union Carbide.
A great deal of variability exists in reports on usage of
2,4,5-T. Agricultural end-use data obtained by EPA from the
National Study of Agricultural, Governmental, and Industrial
Uses of Pesticides, indicated the following uses of 2,4,5-T
in the United States in 1974.
Crop
Pounds AI
Applied
% Total
Agriculture
Rangeland and Pastures
Rice
Nursery Crop
Turf and Ornamentals
Estimated total use in
agriculture for 1974
968,000
16,000
12,000
200
996,000
97.24
1.54
1.20
0.02
100.00
In addition, this survey reported that 324,491 pounds of
active 2,4,5-T were used by Federal and state agencies and
659,463 pounds by industry.
Other sources have reported usages in 1974 as follows:
rights-of-way, 4 million pounds; rangeland, 1.5 to 2.3 million
pounds; rice, 220,000 pounds; and forestry, 50,000 pounds.
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THE REGULATORY HISTORY OF 2,4,5-T
2,4,5-T has been registered as a pesticide in the United
States since 1948. It and its contaminant TCDD, produced
during the manufacturing process, gained national attention
in the late 1960's as ingredients of Herbicide Orange, a
defoliant used by the Department of Defense in Vietnam to
strip vast acreages of forested land. The Herbicide, a mix-
ture of 2,4-D and 2,4,5-T, contained widely varying amounts
of TCDD. Depending upon the manufacturer, TCDD contamination
ranged from very low levels to an approximate high of 50 parts
per million (ppm). Average TCDD was estimated to be 2.9 ppm.
In June and July 1969, newspapers carried reports of increased
occurrences of birth defects in Vietnam. The incidents were
attributed to pre-natal exposure to Herbicide Orange. At
about the same time, results of a screening study conducted
by Bionetics Research Laboratories were released showing that
mice and rats treated during early pregnancy with large doses
of 2,4,5-T gave birth to defective offspring.
In April 1970, as a result of the Bionetics test and others
with similar findings the United States Department of Agri-
culture (USDA) suspended 2,4,5-T products bearing certain
directions for use. The suspended uses were all uses in
lakes, ponds, or on ditch banks; and liquid formulations for
use around the home, recreation areas, and similar sites.
A Notice issued by the USDA on May 1, 1970, cancelled 2,4,5-T
products bearing certain uses. The cancelled uses were all
granular 2,4,5-T formulations for use around the home,
recreational areas, and similar sites; and all 2,4,5-T uses
on food crops intended for human consumption.
All registrants were advised of these actions, and two of
the registrants, Dow Chemical and Hercules Incorporated,
exercised their right under Section 4.e of the Federal Insec-
ticide, Fungicide, and Rodenticide Act (FIFRA) to petition
for referral of the matter (for the cancellation of rice only)
to an Advisory Committee.
Subsequently in 1971 nine scientists were selected from a
National Academy of Sciences list to participate on an
Advisory Committee studying the 2,4,5-T issue. The Committee
was asked to consider all the relevant facts and submit a
report and recommendations for certain registered uses of
2,4,5-T. They were to state the reasons and bases for these
recommendations.
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The report was submitted to the Administrator of the newly
formed Environmental Protection Agency (EPA) on May 7, 1971.
The Committee recommendations adopted by EPA were that use
of 2,4,5-T be permitted in forestry, range land, and rights-
of-way providing that the limit of 0.1 parts per million
(ppm) of contamination with TCDD be set for all future pro-
duction, of 2,4,5-T; that 2,4,5-T be applied with proper
caution so that it will not contaminate other areas where it
may come into contact with humans.
The Committee also recommended that this action be reviewed
again when existing deficiencies in information about possible
magnification of TCDD in the food chain have been rectified
by specific research.
In July 1972, Dow Chemical obtained an injunction against EPA
enjoining further administrative action against 2,4,5-T. In
1973, the United States Court of Appeals for the Eighth Cir-
cuit overturned the injunction and administrative proceedings
were allowed to go forward. Accordingly, a notice of intent
to hold Public Hearings on all uses of 2,4,5-T was filed with
the EPA hearing Clerk on July 20, 1973. All Federally-approved
uses of 2,4,5-T alleged to have caused adverse effects on
human and animal health, were to be explored in a public
hearing scheduled for April 1974, after completion of an
intensive monitoring program in the parts per trillion (ppt)
range. The basic question to be addressed through the hearing
process by EPA was whether the remaining Federal registration
of 2,4,5-T for use on grazing lands, rights-of-way, and rice
should be cancelled or the classification changed.
On May 10, 1974, the information hearing was expanded to
include all insecticides and herbicides having in their manu-
facturing process 2,4,5-trichlorophenol (the precursor of
TCDD). Included were the pecticides silvex, erbon, and
ronnel all of which have the potential of containing TCDD.
On July 24, 1974, EPA withdrew cancellation and information-
gathering proceedings initiated against 2,4,5-T and related
compounds because of its inability to monitor food for
residues of TCDD with the necessary analytical precision.
Although the 2,4,5-T notice of hearing was withdrawn, the
Agency stated that it "will continue its TCDD residue
monitoring program and will take such further action as it
deems appropriate once the results of the monitoring project
are available".
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On July 25-26, 1974 the Agency held a Dioxin Planning
Conference in Washington, D.C. primarily for those parties
having an interest in the withdrawn 2,4,5-T/dioxin hearings.
The nature of the meeting was to address data analysis and
retrieval (in the areas of analytical methodology, toxicology
and monitoring) with emphasis on analytical methodology for
TCDD at the parts per trillion level (ppt). As a result,
EPA established a Dioxin Implementation Plan (DIP) intended
to identify a preferable analytical methodology to monitor
human and environmental samples for TCDD.
On-going TCDD studies under the DIP include: an analytical
method validation study to produce statistically defensible
data; monitoring for residues in human milk in the Pacific
Northwest; additional beef fat residue studies; additional
technical pesticide residue studies; and an environmental
monitoring program for TCDD residues in soil, water and
biota.
»
In 1978, in support of the EPA Special Pesticide Review Divi-
sion's Rebuttable Presumption Against Registration (RPAR)
activities on 2,4,5-T, Region IX (SF) and Region X (Seattle)
collected human milk and urine samples to be studied for
presence of detectable amounts of TCDD in parts per trillion
(ppt) range. One hundred and five samples were collected
starting in November 1977 and ending in February 1978.
Alaska control 25
California control 22
California exposed 20
Oregon exposed 20
Washington exposed 18
Total control 47
Total exposed 58
Grand Total 105
All milk and urine samples were shipped to EPA, Pesticide
Monitoring Laboratory located in Bay St. Louis, Mississippi.
Here the milk samples were extracted and sent to EPA Research
Triangle Park in North Carolina to conduct the first set of
analysis. Confirmatory analysis will be contracted to
independent laboratories. The urine sample will not be
analyzed unless a positive TCDD value is found in the corres-
ponding milk sample.
Completion of the analysis, confirmation and release of the
data is estimated between January and July 1979.
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EPA issued a Rebuttable Presumption Against Registration
(RPAR) on 2,4,5-T in April 1978. RPAR, an in depth review
and risk/benefit analysis the Agency conducts on suspect
pesticides, is fully explained on accompanying RPAR Fact
Sheet.
The Presumption Against Registration of 2,4,5-T was issued on
the basis of laboratory tests which indicate the chemical
induces oncogenic effects (causes tumors) and teratogenic
(birth defects) and/or fetotoxic effects (poisoning of the
fetus) in mammalian test species.
The comment deadline for submittal of information to rebut
or support the Presumption was August 4, 1978. Currently,
EPA is organizing and reviewing the information submitted on
2,4,5-T risks and benefits. The Administrator of EPA,
Douglas Costle, is expected to make a decision on the 2,4,5-T
RPAR during the Spring of 1979. The outcome of this decision
could be continuation of all present uses of 2,4,5-T^
restricted use of the chemical, or total cancellation of all
registrations. Until a decision is reached, all present uses
and registrations of the chemical may continue.
Although the official RPAR comment period has closed, comments
on the 2,4,5-T issue may be sent to:
Steven D. Jellinek, Assistant Administrator
for Toxic Substances
Environmental Protection Agency
Room E637, TS-788
401 "M" Street, S.W.
Washington DC 20460
The Federal Register Section
Technical Services Division, WH-569
Office of Pesticide Programs
U.S. Environmental Protection Agency
Room 401 East Tower
401 "M" Street, S.W.
Washington DC 20460
This information addresses EPA's actions and policies on
2,4,5-T. While the Agency has primary responsibility for
use of the chemical, other Federal, State, and local agencies
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have interests in the use. For further information on
2,4,5-T regulations or use in your area, you may wish to
contact the U.S. Department of Agriculture, the U.S. Forest
Service, your County Agricultural Commissioner, the Water
Quality Control Board, your State Department of Food and
Agriculture, and other Regional and local groups.
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FACT SHEET
REBUTTABLE PRESUMPTION AGAINST REGISTRATION
Open Decisions on Pesticide Safety
In 1972, Congress amended the Federal pesticides law to
require stricter human health and environmental protection
from pesticide abuse. EPA was charged with issuing rules
for reviewing all pesticides to ensure they meet the new
safety requirements. Some 35,000 pesticides consisting of
1,400 basic ingredients are now sold in the U.S. A key part
of the EPA safety review is a process called "Rebuttable
Presumption Against Registration" or "RPAR." It has been in
effect for two years.
*•"
' Jtebuttable presumption ajgjains.t-reg-is.tra_tipn means that if a
i'peslficide shows potentially dangerous characteristics, it is
I subjected to inteiis.i.v.e_^cientific review and public comment
; before_a~decision is made on whether" to allow "continued use
.LqiT'begin the process of removing 'irt "from "the market." "'" "
The hazardous criteria that trigger rebuttable presumption
are: if the pesticide is highly toxic and may pose the
threat of immediate poisoning to people or wildlife, if it
may cause long-term health problems, such as cancer or birth
defects, if it may cause significant reductions in nontarget
animals, or fatality to members of endangered species, or if
the pesticide lacks an emergency first-aid treatment.
If a pesticide ingredient meets one or more of the risk
criteria mentioned above, the rebuttable presumption process
comes into play as follows:
1. Manufacturers and users of the suspect pesticide,
and the general public, are notified of the risk
information and given 45 days to offer rebuttal evi-
dence. This period for submitting views may be extended
by 60 days.
2. At the end of this period, EPA announces whether
or not all risks have been rebutted.
3. If they have, EPA proposes to allow continued use
of the pesticide. If they have not, an internal
analysis of risks versus benefits is undertaken. Up
to 180 days may have elasped by this time, and the
pesticide in question may continue to be sold.
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4. Depending upon the outcome of the risk/benefit
analysis, the pesticide is proposed for approval, or
EPA begins formal consultation with the U.S. Department
of Agriculture on the economic impact and sales. An
independent Scientific Advisory Panel reviews health
and environmental effects information.
5. Roughly 60 days after the USDA and scientific
consultation, EPA must again decide whether to propose
continued use of the pesticide or issue a "notice of
intent to cancel" further production and sale. Regard-
less of which way the decision goes, the opportunity
for a public hearing exists.
A "notice of intent to cancel" represents EPA's finding that
a. pesticide generally causes unreasonable adverse effects
upon the environment. It provides manufacturers and users
of the pesticide and other interested persons the chance to
request courtroom-type hearings on risks and benefits.
Depending upon the complexity of the issues these hearings
may; last a year or longer. The eventual outcome is a decision
by the EPA Administrator on the pesticide's future. During
cancellation hearings, the pesticide may continue to be sold.
"Suspension" may interrupt either the rebuttable presumption
or cancellation process at any point. It is based upon a
finding of imminent hazard posed by the pesticide. A brief
public hearing may be held. (The exact length of this hearing
may be determined by the EPA Administrator.) The purpose of
a suspension is to decide whether to allow continued sale of
a pesticide during the time it would take to hold more in-depth
cancellation hearings.
EPA's pesticide registration rules, including the rebuttable
presumption process, appeared in the July 3, 1975 Federal
Register.
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