United States
Environmental Protection
Agency
Office of Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-92-014
December 1992
R.E.D. FACTS
Pesticide
Registration
Oxalic Acid
All pesticides sold or used 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 undue hazards to human health or the environment.
When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Document, or RED. This fact
sheet summarizes the information in the RED for oxalic acid.
Use Profile
Regulatory
History
Oxalic acid is registered for use as a disinfectant to control bacteria
and germs, and as a sanitizer, in toilet bowls, urinals and bathroom
premises. Registered products are formulated as ready-to-use liquids or
solid soluble concentrates, and are applied by sprinkling, pouring, brushing,
swabbing or mopping the product onto the surface to be treated.
Oxalic acid also has many diverse, non-pesticidal, manufacturing and
industrial uses including use in fabric printing and dyeing; bleaching straw
hats; removing paint, varnish, rust or ink stains; and cleaning wood.
Oxalic acid first was registered as a pesticide in 1957 for the current
bathroom disinfectant uses, as well as use in swimming pool water systems,
drainage systems, sewage systems, eating establishments (to disinfect
equipment and utensils), and other sites. At present, five products
containing oxalic acid are registered.
Oxalic acid is exempt from the requirement of a tolerance (or legal
residue limit) when it is used as an inert ingredient in pesticide formulations
that are applied to growing or harvested crops. EPA also is regulating
oxalic acid under its Inerts Strategy.
Human Health Toxicity
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Assessment
Oxalic acid is a substance that occurs naturally in many plants and
vegetables, and also is a product of the metabolism of molds. It is a widely
used chemical whose toxicity is well known. In assessing oxalic acid's risks
to people, EPA relied on articles in published scientific literature.
Oxalic acid is corrosive to the eyes and skin, and has been placed in
Toxicity Category I (indicating the highest degree of toxicity) for acute eye
and skin irritation effects. It also is highly irritating and damaging to the
respiratory system if inhaled. Acute exposure also causes stomach
irritation, lowered calcium levels, effects to the nervous system and kidney
damage in humans.
A subchronic inhalation study in rats showed decreased body weights,
restricted growth and disrupted estrous cycles. At the highest dose, the test
animals also had reduced thyroid weights and changes in iodine and
hormone levels. Metabolism studies show that excess levels of oxalic acid
cause kidney damage in mammals. Chronic oral intake in animals produces
kidney damage and disturbances in the metabolism of calcium. A
multigeneration mouse reproduction study showed reproductive effects and
parental toxicity at the highest dose level.
Occupational and Residential Exposure
The potential for significant eye and dermal exposure exists when
workers or homeowners apply bathroom disinfectant products containing
oxalic acid and other active and inert ingredients. These products are liquid
and granular formulations applied using brushes, swabs or mops.
Exposure, especially to the concentrated formulations, can cause chemical
burns to the skin and severe to permanent damage to the eyes.
Environmental
Assessment
Human Risk Assessment
Although they contain only a small amount of oxalic acid and a much
greater amount of other active and inert ingredients, oxalic acid products as
formulated and registered for use as bathroom disinfectants can be highly
irritating and damaging to the eyes, skin and mucous membranes. Exposure
to the concentrated formulations can result in chemical burns to the skin and
severe to permanent eye damage. However, these risks should be low as
long as product label directions and precautions are followed.
Environmental Fate
EPA relied on data available in the scientific literature to assess the
environmental fate and transport of oxalic acid used as a pesticide. Oxalic
acid occurs widely in nature—it is present in the tissues of many plants and
algae, serving both to excrete and store calcium. In water, its negative ion
forms complexes with a number of metal ions; and oxalic acid is
immobilized as a result of this formation of complexes. Both aerobic and
anaerobic conditions biodegrade oxalic acid in less than one day.
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Oxalic acid, used as an indoor disinfectant, degrades readily and
rapidly under both aerobic and anaerobic conditions during sewage
treatment. Sewage effluents discharged to natural waters are not expected to
contain oxalic acid residues from its use as a pesticide. Any oxalic acid
present in the environment is the result of natural processes and not from
use of the chemical as a bathroom disinfectant.
Ecological Effects
EPA did not require or evaluate ecological effects data for oxalic acid
because the pesticide is only used indoors and exposure to wildlife is not
expected to occur. However, three studies are being required to assess the
toxicity of the pesticide to wildlife in case of a spill. The results of these
studies will be used to develop product labeling statements.
EPA is requiring three acute toxicity studies on birds, freshwater fish
and invertebrate species, to determine oxalic acid's toxicity hazard to
wildlife in case of a transportation accident and develop appropriate product
label statements. All other generic data requirements have been waived.
Product-specific data, including product chemistry and efficacy
studies, also are required for reregistration of oxalic acid. Additional label
precautions may be required, depending on the results of these studies.
Product LabGling The labels of all registered oxalic acid products must comply with
ChanCIGS RGCIUirGd ^PA's current pesticide labeling requirements. The Agency may require
additional label directions and precautions, depending on the results of the
studies mentioned above.
Additional Data
Required
Regulatory
Conclusion
• The pesticide oxalic acid will not result in unreasonable adverse
effects to human health or the environment, and all registered products
containing oxalic acid are eligible for reregistration. These products will be
reregistered once the required product-specific data and revised labeling are
received and accepted by EPA.
• Registered products containing oxalic acid as well as other active
ingredients will be reregistered once the other active ingredients also are
determined to be eligible for reregistration.
For More
Information
EPA is requesting public comments on the Reregistration Eligibility
Document (RED) for oxalic acid 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 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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In the future, the oxalic acid RED 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 oxalic acid or about EPA's pesticide
reregistration program, please contact the Special Review and Reregistration
Division (7508W), OPP, US EPA, Washington, DC 20460, telephone 703-
308-8000. For information about reregistration of individual oxalic acid
products, please contact Arvella Farmer, Registration Division (7505C),
OPP, US EPA, Washington, DC 20460, telephone 703-305-6939.
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, 24 hours a day, seven days a week, or fax your
inquiry to 806-743-3094.
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