United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-93-011
September 1993
R.E.D. FACTS
Pesticide
Reregistration
Use Profile
Glyphosate
All pesticides sold or distributed in the United States must be registered
by EPA, based on scientific studies showing that they can be used without
posing unreasonable risks to people or the environment. Because of advances
in scientific knowledge, the law requires that pesticides which were first
registered years ago be reregistered to ensure that they meet today's more
stringent standards.
In evaluating pesticides for reregi strati on, EPA obtains and reviews a
complete set of studies from pesticide producers, describing the human health
and environmental effects of each pesticide. The Agency imposes any
regulatory controls that are needed to effectively manage each pesticide's
risks. EPA then reregisters pesticides that can be used without posing
unreasonable risks to human health or the environment.
When a pesticide is eligible for reregi strati on, EPA announces this and
explains why in a Reregistration Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED document for glyphosate.
Glyphosate is a non-selective herbicide registered for use on many food
and non-food field crops as well as non-crop areas where total vegetation
control is desired. When applied at lower rates, glyphosate also is a plant
growth regulator.
Glyphosate is among the most widely used pesticides by volume. It
ranked eleventh among conventional pesticides used in the U.S. during 1990-
91. In recent years, approximately 13 to 20 million acres were treated with
18.7 million pounds of glyphosate annually. The largest use sites include
hay/pasture, soybeans and field corn.
Three salts of glyphosate are used as active ingredients in registered
pesticide products. Two of these active ingredients, plus technical grade
glyphosate, are contained in the 56 products that are subject to this RED.
The isopropylamine salt, an active ingredient in 53 registered products,
is used as a herbicide to control broadleaf weeds and grasses in many food
and non-food crops and a variety of other sites including ornamentals, lawns
and turf, residential areas, greenhouses, forest plantings and industrial rights-
of-way. It is formulated as a liquid, solid or pellet/tablet, and is applied using
ground or aerial equipment.
-------
The sodium salt of glyphosate, an active ingredient in two registered
pesticide products, is used as a plant growth regulator for peanuts and
sugarcane, to modify plant growth and hasten the ripening of fruit. It is
applied as a ground spray to peanut fields and as an aerial spray to sugarcane.
Preharvest intervals are established for both crops.
The monoammonium salt of glyphosate is an active ingredient in an
additional seven herbicide/growth regulator products. This form of
glyphosate was initially registered after November 1984, so it is not subject to
reregi strati on or included in this RED. However, in reassessing the existing
glyphosate tolerances (maximum residue limits in or on food and feed), EPA
included those for the monoammonium salt.
Regulatory
History
EPA issued a Registration Standard for glyphosate in June 1986 (NTIS
PB87-103214). The Registration Standard required additional phytotoxicity,
environmental fate, toxicology, product chemistry and residue chemistry
studies. All of the data required have been submitted and reviewed, or were
waived.
Human Health
Assessment
Toxicity
Glyphosate is of relatively low oral and dermal acute toxicity. It has
been placed in Toxicity Category III for these effects (Toxicity Category I
indicates the highest degree of acute toxicity, and Category IV the lowest).
The acute inhalation toxicity study was waived because glyphosate is non-
volatile and because adequate inhalation studies with end-use products exist
showing low toxicity.
A subchronic feeding study using rats showed blood and pancreatic
effects. A similar study with mice showed reduced body weight gains in both
sexes at the highest dose levels. A dermal study with rabbits showed slight
reddening and swelling of the skin, decreased food consumption in males and
decreased enzyme production, at the highest dose levels.
Several chronic toxicity/carcinogenicity studies using rats, mice and
beagle dogs resulted in no effects based on the parameters examined, or
resulted in findings that glyphosate was not carcinogenic in the study. In June
1991, EPA classified glyphosate as a Group E oncogen—one that shows
evidence of non-carcinogenicity for humans—based on the lack of convincing
evidence of carcinogenicity in adequate studies.
In developmental toxicity studies using pregnant rats and rabbits,
glyphosate caused treatment-related effects in the high dose groups including
diarrhea, decreased body weight gain, nasal discharge and death.
One reproductive toxicity study using rats showed kidney effects in the
high dose male pups; another study showed digestive effects and decreased
body weight gain. Glyphosate does not cause mutations.
-------
In one metabolism study with rats, most of the glyphosate administered
(97.5 percent) was excreted in urine and feces as the parent compound; less
than one percent of the absorbed dose remained in tissues and organs,
primarily in bone tissue. Aminomethyl phosphonic acid (AMPA) was the
only metabolite excreted. A second study using rats showed that very little
glyphosate reaches bone marrow, that it is rapidly eliminated from bone
marrow, and that it is even more rapidly eliminated from plasma.
Dietary Exposure
The nature of glyphosate residue in plants and animals is adequately
understood. Studies with a variety of plants indicate that uptake of glyphosate
or AMPA from soil is limited. The material which is taken up is readily
translocated throughout the plant and into its fruit. In animals, most
glyphosate is eliminated in urine and feces. Enforcement methods are
available to detect residues of glyphosate and AMPA in or on plant
commodities, in water and in animal commodities.
85 tolerances have been established for residues of glyphosate and its
metabolite, AMPA, in or on a wide variety of crops and crop groups, as well
as in many processed foods, animal feed and animal tissues (please see 40
CFR 180.364, 40 CFR 185.3500 and 40 CFR 186.3500). EPA has reassessed
the existing and proposed tolerances for glyphosate. Though some
adjustments will be needed, no major changes in existing tolerances are
required. EPA also has compared the U.S. tolerances with international
Codex maximum residue limits (MRLs), and is recommending certain
adjustments to achieve greater compatibility.
EPA conducted a dietary risk assessment for glyphosate based on a
worst-case risk scenario, that is, assuming that 100 percent of all possible
commodities/acreage were treated, and assuming that tolerance-level residues
remained in/on all treated commodities. The Agency concluded that the
chronic dietary risk posed by glyphosate food uses is minimal.
A reference dose (RfD), or estimate of daily exposure that would not
cause adverse effects throughout a lifetime, of 2 mg/kg/day has been proposed
for glyphosate, based on the developmental toxicity studies described above.
Occupational and Residential Exposure
Occupational and residential exposure to glyphosate can be expected
based on its currently registered uses. However, due to glyphosate's low acute
toxicity and the absence of other toxicological concerns (especially
carcinogenicity), occupational and residential exposure data are not required
for reregi strati on.
Some glyphosate end-use products are in Toxicity Categories I or II for
primary eye irritation or skin irritation. In California, glyphosate ranks high
among pesticides causing illness or injury to workers, who report numerous
incidents of eye and skin irritation from splashes during mixing and loading.
-------
Environmental
Assessment
EPA is not adding any personal protective equipment (PPE) requirements at
this time, but any existing PPE label requirements must be retained.
The Worker Protection Standard (WPS) for Agricultural Pesticides
(please see 40 CFR 156 and 170) established an interim restricted entry
interval (REI) of 12 hours for glyphosate. The Agency has decided to retain
this REI as a prudent measure to mitigate risks to workers. During the REI,
workers may reenter areas treated with glyphosate only in the few, narrow
exceptions allowed in the WPS. The REI applies only to glyphosate uses
within the scope of the WPS, so homeowner and commercial uses are not
included.
Human Risk Assessment
EPA's worst case risk assessment of glyphosate's many registered food
uses concludes that human dietary exposure and risk are minimal. Existing
and proposed tolerances have been reassessed, and no significant changes are
needed to protect the public.
Exposure to workers and other applicators generally is not expected to
pose undue risks, due to glyphosate's low acute toxicity. However, splashes
during mixing and loading of some products can cause injury, primarily eye
and skin irritation. EPA is continuing to recommend PPE, including
protective eye wear, for workers using end-use products that are in Toxicity
Categories I or II for eye and skin irritation. To mitigate potential risks
associated with reentering treated agricultural areas, EPA is retaining the 12
hour REI set by the WPS.
Environmental Fate
Glyphosate adsorbs strongly to soil and is not expected to move
vertically below the six inch soil layer; residues are expected to be immobile
in soil. Glyphosate is readily degraded by soil microbes to AMPA, which is
degraded to carbon dioxide. Glyphosate and AMPA are not likely to move to
ground water due to their strong adsorptive characteristics. However,
glyphosate does have the potential to contaminate surface waters due to its
aquatic use patterns and through erosion, as it adsorbs to soil particles
suspended in runoff. If glyphosate reached surface water, it would not be
broken down readily by water or sunlight.
Ecological Effects
Glyphosate is no more than slightly toxic to birds and is practically non-
toxic to fish, aquatic invertebrates and honeybees. Due to the presence of a
toxic inert ingredient, some glyphosate end-use products must be labeled,
"Toxic to fish," if they may be applied directly to aquatic environments.
Product labeling does not preclude off-target movement of glyphosate by
drift. EPA therefore is requiring three additional terrestrial plant studies to
assess potential risks to nontarget plants.
EPA does not expect that most endangered terrestrial or aquatic
organisms will be affected by the registered uses of glyphosate. However,
-------
many endangered plants as well as the Houston toad (due to its habitat) may
be at risk. EPA is deferring any use modifications or labeling amendments
until it has published the Endangered Species Protection Plan and has given
registrants guidance regarding endangered species precautionary labeling.
Additional Data
Required
Product Labeling
Changes Required
Ecological Effects Risk Assessment
Based on current data, EPA has determined that the effects of
glyphosate on birds, mammals, fish and invertebrates are minimal. Under
certain use conditions, glyphosate may cause adverse effects to nontarget
aquatic plants. Additional data are needed to fully evaluate the effects of
glyphosate on nontarget terrestrial plants. Risk reduction measures will be
developed if needed, once the data from these studies are submitted and
evaluated.
EPA is requiring three generic studies (Tier II Vegetative Vigor,
Droplet Size Spectrum, and Drift Field Evaluation) which are not part of the
target data base and do not affect the reregi strati on eligibility of glyphosate.
The Agency also is requiring product-specific data including product
chemistry and acute toxicity studies, as well as revised Confidential
Statements of Formula and revised labeling.
All end-use glyphosate products must comply with EPA's current
pesticide product labeling requirements. In addition:
• Protection of Aquatic Organisms
Non-Aquatic Uses - End-use products that are not registered for aquatic
uses must bear the following label statement:
Do not apply directly to water, to areas where surface water is present
or to intertidal areas below the mean high water mark. Do not
contaminate water when disposing of equipment washwaters and
rinsate.
Aquatic Uses - End-use products registered for aquatic uses must bear
the following label statement:
Do not contaminate water when disposing of equipment washwaters and
rinsate. Treatment of aquatic weeds can result in oxygen loss from
decomposition for dead plants. This loss can cause fish kills.
• Worker Protection Standard (WPS) Requirements
Any product whose labeling permits use in the production of an
agricultural plant on any farm, forest, nursery or greenhouse must comply
with the labeling requirements of:
• PR Notice 93-7, "Labeling Revisions Required by the Worker
Protection Standard (WPS)," and
-------
• PR Notice 93-11, "Supplemental Guidance for PR Notice 93-7."
Unless specifically directed in the RED, all statements required by these two
PR Notices must appear on product labeling exactly as instructed in the
Notices. Labels must be revised by April 21, 1994, for products distributed or
sold by the primary registrant or supplementally registered distributors, and
by October 23, 1995, for products distributed or sold by anyone.
• Personal Protective Equipment (PPE)
No new PPE requirements must be added to glyphosate labels.
However, any existing PPE requirements on labels must be retained.
• Entry Restrictions
Products Not Primarily Intended for Home Use:
0 Uses Within the Scope of the WPS - A 12-hour restricted entry
interval (REI) is required for all products with uses within the scope of
the WPS, except products intended primarily for home use. The PPE
for early entry should be that required for applicators of glyphosate,
except any applicator requirement for an apron or respirator is waived.
This REI and PPE should be inserted into the standardized statements
required by PR Notice 93-7.
• Sole Active Ingredient End-Use Products - Labels must be
revised to adopt the entry restrictions set forth in this section.
Any conflicting entry restrictions on current labeling must be
removed.
• Multiple Active Ingredient Products - Registrants must compare
the entry restrictions set forth in this section to those on their
current labeling and retain the more protective. A specific time
period in hours or days is considered more protective than "until
sprays have dried" or "dusts have settled."
Regulatory
Conclusion
0 Uses Not Within the Scope of the WPS - No new entry restrictions
must be added. However, any entry restrictions on current product
labeling with these uses must be retained.
Products Primarily Intended for Home Use:
0 No new entry restrictions must be added. However, any entry
restrictions on current product labeling must be retained.
The use of currently registered pesticide products containing the
isopropylamine and sodium salts of glyphosate in accordance with the
labeling specified in this RED will not pose unreasonable risks or adverse
effects to humans or the environment. Therefore, all uses of these products
are eligible for reregi strati on.
These glyphosate products will be reregistered once the required
product-specific data, revised Confidential Statements of Formula and revised
labeling are received and accepted by EPA.
-------
For More
Information
Products which contain active ingredients in addition to glyphosate will
not be reregistered until all their other active ingredients also are eligible for
reregi strati on.
EPA is requesting public comments on the Reregi strati on Eligibility
Decision (RED) document for glyphosate during a 60-day time period, as
announced in a Notice of Availability published in the Federal Register. To
obtain a copy of the RED document or to submit written comments, please
contact the Pesticide Docket, Public Response and Program Resources
Branch, Field Operations Division (7506C), Office of Pesticide Programs
(OPP), US EPA, Washington, DC 20460, telephone 703- 305-5805.
Following the comment period, the glyphosate RED document will be
available from the National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161, telephone 703-487-4650.
For more information about EPA's pesticide reregi strati on program, the
glyphosate RED, or reregi strati on of individual products containing
glyphosate, please contact the Special Review and Reregi strati on Division
(7508W), OPP, US EPA, Washington, DC 20460, telephone 703-
308-8000.
For information about the health effects of pesticides, or for assistance
in recognizing and managing pesticide poisoning symptoms, please contact
the National Pesticides Telecommunications Network (NPTN). Call toll-free
1-800-858-7378, between 8:00 am and 6:00 pm Central Time, Monday
through Friday.
------- |