United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-93-016
September 1993
R.E.D. FACTS
Tris(hydroxymethyl)-
nitromethane
Pesticide
Reregistration
Use Profile
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 reregistration, 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 reregistration, EPA announces this and
explains why in a Reregistration Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED document for the
reregistration case Tris(hydroxymethyl) nitromethane, which contains the
active ingredient 2-(hydroxymethyl)-2-nitro-l,3-propanediol.
2-(hydroxymethyl)-2-nitro-l,3-propanediol is used as a microbicide
and bacteriostat in disinfectants and industrial preservatives. Specifically, it
is used as an industrial preservative in metalworking fluids, secondary oil
field recovery waters, paper mills and commercial/industrial water cooling
systems; as an in-can preservative in latex paints, polishes and detergents;
and as a disinfectant to control disease organisms in livestock and poultry
areas on farm premises and equipment. It is formulated as a soluble liquid
concentrate, powder or pellets, and is applied through use of a metering
pump in industrial water systems, by pouring into paints and polishes, and
as a spray to farm areas and equipment.
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Regulatory
History
Human Health
Assessment
2-(hydroxymethyl)-2-nitro-l,3-propanediol was first registered in the
U.S. in 1955, as an industrial bactericide and slimicide. EPA has issued
three relevant Data Call-In (DCI) Notices: the Antimicrobial DCI in March
1987, the comprehensive reregistration Phase 4 DCI in September 1992,
and a third DCI in August 1993, the latter for residue data. Currently, nine
pesticide products are registered which contain this active ingredient.
Toxicity
Studies using laboratory animals indicate that 2-(hydroxymethyl)-2-
nitro-l,3-propanediol is of low to moderate acute toxicity to mammals. It
has been placed in Toxicity Category III for acute oral, dermal and
inhalation effects (Toxicity Category I indicates the greatest degree of acute
toxicity and Category IV the lowest). It has been placed in Category IV for
eye and skin irritation effects. Since these studies were not conducted with
the technical grade (100%) powder, additional confirmatory acute inhalation
and eye irritation studies are required using that formulation.
In a subchronic dermal toxicity study using rats, there were no
treatment-related effects observed at any dose level. In developmental
toxicity studies using rats and rabbits, treatment-related maternal effects
were observed in the high-dose groups. No mutagenic effects were seen in
a battery of studies.
2-(hydroxymethyl)-2-nitro-l,3-propanediol decomposes to
formaldehyde under alkaline, warm conditions. Formaldehyde has been
classified by EPA as a Group Bl "probable" human carcinogen. The
toxicity of formaldehyde has been a primary consideration in evaluating the
risks of 2-(hydroxymethyl)-2-nitro-l,3-propanediol.
Dietary Exposure
No dietary exposure is expected as a result of the registered uses of 2-
(hydroxymethyl)-2-nitro-l,3-propanediol. Its one potential food use, as a
disinfectant in or on livestock premises and equipment, has been modified to
delete milk house and milking equipment uses, and to add restrictions to
poultry house uses which eliminate the means of exposure of edible
livestock tissue or eggs. Therefore, no tolerances (maximum residue limits)
or exemptions from tolerances are required.
Occupational and Residential Exposure
2-(hydroxymethyl)-2-nitro-l,3-propanediol has many uses that may
involve exposure to workers, and exposure monitoring data were required to
estimate combined inhalation and dermal exposure of mixers, loaders and
applicators in various use sites.
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Worker exposure is considered significant for preservative and pulp
and paper mill uses, which involve open pouring methods. However,
associated risks will be mitigated ten-fold by requiring use of a respirator
and personal protective equipment (PPE) including a long-sleeved shirt and
long pants, and shoes plus socks.
Worker exposure is considered low for the poultry/livestock
disinfectant use, but is of concern since formaldehyde is an active ingredient
in the product, and since a spray method of application is involved. Use of
PPE and a respirator are required, and will reduce any exposure ten-fold.
Worker exposure during cooling tower and metal working fluid uses is
considered very low. Again, PPE is required to reduce possible exposure to
formaldehyde.
While post-application worker exposure to formaldehyde is minimal
for most uses of 2-(hydroxymethyl)-2-nitro-l,3-propanediol, the disinfectant
spray used in livestock/poultry premises, which contains the active
ingredient formaldehyde, causes post-application exposure of concern.
However, EPA's exposure estimate represents the worst case scenario, and
OSHA requires monitoring for formaldehyde before workers may reenter
treated premises. Therefore, post-application worker exposure is likely the
same or less than exposure during mixing, loading or applying the pesticide.
Similarly, post-application worker exposure to formaldehyde from use
of the parent chemical in pulp and paper mills is of some concern. Since
the Agency's exposure estimate is very conservative, a post-application
inhalation exposure monitoring study is required only as confirmatory data.
Human Risk Assessment
Since 2-(hydroxymethyl)-2-nitro-l,3-propanediol has no food uses, no
dietary risk exists. Overall, minimal risk and exposure are associated with
the use of this active ingredient. The risks associated are due to its
degradation product, formaldehyde.
EPA has examined the cancer risks of formaldehyde extensively.
Using the most widely accepted risk assessment methodology, the Agency
has estimated the refined upper bound cancer risk to mixers, loaders and
applicators from exposure to formaldehyde through use of 2-
(hydroxymethyl)-2-nitro-l,3-propanediol. With PPE and respirators, these
risks range from 1.1 in 100,000 for preservative uses to 2.5 in 1,000,000
for poultry/livestock disinfectant uses.
Post-application worker exposure to formaldehyde following the
livestock/poultry premise spray use is of concern; the upper bound risk to
workers is estimated to be 2.5 in 1,000,000. However, the Agency's
exposure estimate represents the worst case scenario. Actual risks to
workers should be lower considering OSHA's formaldehyde monitoring
requirements. Post-application exposure of pulp and paper mill workers is
conservatively estimated to be 2.7 in 100,000. A post-application inhalation
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exposure monitoring study is required for this use, as confirmatory information.
In evaluating environmental effects, EPA focused on 2-
AsSGSSITIGnt (hydroxymethyl)-2-nitro-l,3-propanediol rather than its degradation
product, formaldehyde. In the aquatic environment, the active ingredient is
relatively stable. As it breaks down to formaldehyde, the latter chemical is
rapidly dissipated. Therefore, the parent compound is of greater interest.
Environmental Fate
Based on the results of an exposure assessment model, the Agency
expects that 2-(hydroxymethyl)-2-nitro-l,3-propanediol used according to
the label will result in minimal exposure to the environment. Concern
would arise only from its discharge into receiving waters from the industrial
uses or in the case of spills, accidents or misuse. A hydrolysis study is
required to confirm the chemical's degradation in the environment.
Ecological Effects
2-(hydroxymethyl)-2-nitro-l,3-propanediol has a low order of acute
oral and dermal toxicity to terrestrial mammals. It may be slightly toxic to
upland game birds, but is practically non-toxic to waterfowl. It also is
practically non-toxic to freshwater fish species on an acute basis. It is
slightly toxic to freshwater aquatic invertebrates and mollusks, and
practically non-toxic to crustaceans.
Ecological Effects Risk Assessment
EPA conducted a Tier Ic Estimated Environmental Concentration
(EEC) model to assess the residue levels of 2-(hydroxymethyl)-2-nitro-l,3-
propanediol in the receiving stream from several use sites. This model
provides a reasonable worst case estimate of the maximum concentration
that may occur immediately downstream from an industrial point source
discharge site. The typical EEC values for all uses of this active ingredient
are below the levels of concern for fish and invertebrates. Therefore, the
pesticide can be used at typical use sites without producing effluent above
levels of concern. Under a high exposure scenario, a high degree of risk
would be posed to aquatic organisms. However, discharge of the pesticide
is regulated by the National Pollutant Discharge Elimination System
(NPDES) permit program administered by EPA. Through this program,
the Agency is able to control the discharge of this pesticide and other
chemicals so that toxic levels are avoided.
Endangered Species
The high exposure scenarios described above exceed the levels of
concern for endangered aquatic organisms. In addition, the typical EEC
value for pulp and paper mills exceeds the level of concern for endangered
aquatic invertebrates. Effluent containing this active ingredient should not
be discharged into streams or waterways where endangered aquatic
organisms are known to reside. EPA is working with the U.S. Fish and
Wildlife Service to develop a program to avoid jeopardizing the continued
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existence of identified species by the use of pesticides. When this program
goes into effect, endangered species labeling will be required.
Additional Data The generic data base for 2-(hydroxymethyl)-2-nitro-l,3-propanediol
RedUJr0d *s substantially complete. However, for confirmatory purposes, EPA is
requiring acute inhalation and eye irritation studies using the technical grade
powder formulation, a post-application inhalation exposure worker
monitoring study, and a hydrolysis study. EPA also is requiring product-
specific data, including chemistry, acute toxicology and efficacy studies, as
well as revised labeling for reregistration.
Product LabGling All end-use products containing 2-(hydroxymethyl)-2-nitro-l,3-
ChanCIGS RGCIUirGd propanediol must comply with EPA's current pesticide product labeling
requirements. In addition:
• Effluent Discharge Statement - All end-use products for indoor non-
food uses (industrial uses which discharge effluent), aquatic non-food
industrial uses, or terrestrial non-food uses must bear the following effluent
discharge statement:
"Do not discharge effluent containing this product into lakes, streams,
ponds, estuaries, oceans or public waters unless in accordance with the
requirements of a National Pollutant Discharge Elimination System
(NPDES) permit and the permitting authority has been notified in
writing prior to discharge. Do not discharge effluent containing this
product to sewer systems without previously notifying the local
sewage treatment plant authority. For guidance contact your State
Water Board or Regional Office of EPA."
• Use Site PPE Requirements and Entry Restrictions
• In poultry/livestock premises, preservative and pulp and paper
mills, the PPE requirement for mixer/loader/applicators is:
"Pesticide handlers must wear:
—Long-sleeved shirt and long pants
—Chemical-resistant gloves
—Shoes plus socks
In addition, when engaged in pouring this product,
—A respirator with either an organic-vapor-removing cartridge with a
prefilter approved for pesticides (MSHA/NIOSH approval number
prefix TC-23C), or a canister approved for pesticides (MSHA/NIOSH
approval number prefix TC-14G)."
• For metal working fluids and cooling tower water uses, the PPE
requirement for mixer/loader/applicators is:
"Pesticide handlers must wear:
—Long-sleeved shirt and long pants
—Chemical-resistant gloves
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Regulatory
Conclusion
—Shoes plus socks"
• In poultry/livestock premises, post-application workers must
observe the following use restriction on the labeling in the directions
describing use as a disinfectant spray:
"Entry by any person—other than a correctly equipped handler—is
PROHIBITED in the entire enclosed building/structure from the start
of application until aeration reduces the air concentration level of
formaldehyde in the working area to less than 0.75 ppm. The air
level concentration of formaldehyde must be measured before entry is
permitted. (OSHA issued a final rule for the PEL for formaldehyde
as 0.75 ppm, May 27, 1992, Federal Register, Vol. 57, p. 22290.)
Any handler who enters the treated area during this entry-restricted
period must wear:
—Long-sleeved shirt and long pants
—Shoes plus socks
—A respirator with either an organic-vapor-removing cartridge with a
prefilter approved for pesticides (MSHA/NIOSH approval number
prefix TC-23C), or a canister approved for pesticides (MSHA/NIOSH
approval number prefix TC-14G)."
The currently registered uses of 2-(hydroxymethyl)-2-nitro-l,3-
propanediol may pose low level cancer risks to workers from the degradate
formaldehyde, and could pose risks to aquatic organisms under certain
conditions as industrial effluent containing the parent chemical is released
into receiving waters. However, the uses will not cause unreasonable
adverse effects to humans or the environment, and are eligible for
reregistration.
Products containing 2-(hydroxymethyl)-2-nitro-l,3-propanediol as the
sole active ingredient will be reregistered once the required product-specific
data and revised labeling are received and accepted by EPA. Products also
containing other active ingredients will be reregistered only after the other
active ingredients also are determined to be eligible for reregistration.
For More
Information
EPA is requesting public comments on the Reregistration Eligibility
Decision (RED) document for Tris(hydroxymethyl)nitromethane 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.
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Following the comment period, the Tris(hydroxymethyl)nitromethane
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 reregistration program,
the Tris(hydroxymethyl)nitromethane RED, or reregistration of individual
products containing the active ingredient 2-(hydroxymethyl)-2-nitro-l,3-
propanediol, please contact the Special Review and Reregistration 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.
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