OBPA EPA R.E.D. Facts
EPA R.E.D. FACTS
1O, 1O'- OXYBISPHENOXARSINE (OBPA)
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
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 its
decision and explains why in a Reregistration Eligibility Document, or
RED. This fact sheet summarizes the information in the RED for 10, 10'-
OBPA is a bacteriostat, disinfectant (bacteriocide/germicide) and fungicide.
It is registered to prevent the growth of microorganisms in plastics which are
fabricated into shower curtains, floor coverings, wall coverings, coated
fabrics, marine upholstery, automotive vinyl trim, vinyl molding, tarpaulins,
awnings, gaskets, weather stripping, caulking, ditch liners and swimming pool
liners. OBPA also is used as a preservative in adhesives, coatings and
specialty products, in paper and paper and plastic products, in textiles,
fibers and cordage, in carpets, and in othcr pesticides.
OBPA is formulated as an emulsifiable concentrate, pelleted/tableted, soluble
concentrate/liquid and ready-to-use liquid. The concentration varies from 1
to 5 percent, based on the total weight of formulation.
OBPA was initially registered as a pesticide in the United States in 1965.
EPA issued a Registration Standard for OBPA in October 1981 (N-IlS PB82-
172271). The Registration Standard required additional product chemistry
data, a hydrolysis study and an activated sludge metabolism study, which was
later waived. In September 1991, EPA issued a Data Call-In (DCI) requinng
product chemistry data and a repeat of the hydrolysis study (which was later
EPA has now completed its rcview of the OBPA data base, including the data
submitted in response to the 1991 DCI.
Human Health Assessment
OBPA shows a high degree of acute toxicity when administered orally and to the
skin and eyes. It has been placed in Toxicity Category I indicating the
highest degree of acute toxicity for these effects.
In subacute feeding studies using rats, animals fed the highest dose levels
had retarded growth, liver effects and an accumulation of arsenic in the liver
and kidneys. In a subacute inhalation study rats and guinea pigs sacrificed
48 hours after their last exposure to OBPA had mild to moderate effects and
the rats had liver effects. Animals kept four months longer with no further
exposure showed no effects of OBPA.
OBPA does not appear to cause developmental or reproductive toxicity, and
shaws no mutagenic activity. Metabolism studies show that arsenic accumulates
in the liver and kidneys as a result of exposure to OBPA, however this arsenic
is cleared from the body after two weeks.
OBPA is not registered for use on food, feed or processed commodities.
Therefore, dietary exposure or risk is not expected.
Occupational and Residential Exposure
Although occupational and residential exposure to OBPA occurs, such exposure
is indirect and/or extremely low level. Dilect occupational exposure during
production of pesticide or plastic products containing OBPA is mitigated by
the use of closed systems and appropriate protective gloves and eyewear.
Indirect residential and other human exposure to OBPA in treated plastics is
low because only a small percent of OBPA is added to these products, and only
small amounts of OBPA are released, very slowly.
Human Risk Assessment
OBPA does not pose human dietary risks since no food-related uses are
registered and dietary aposure is not anticipated.
The potential for occupational cxposure to OBPA is minimal provided that OBPA
is used in a closed system and that appropriate Personal Protective Equipment
(PPE) is worn. Residential exposure to OBPA is indirect and low level. No
additional uses are proposed that would significantly increase human exposux
to OBPA. Therefore, the potential human risks from exposure to OBPA
pesticides are likely to be minimal.
No further environmental fate data are needed because of the very limited
environmental exposure expected from current uses of OBPA. The Registration
Standard required an activated sludge study, which was later waived, and a
hydrolysis study. The hydrolysis study was found deficient, but the Agency
later determined that an additional hydrolysis study was not needed based on
the fact that OBPA-treated materials will not result in significant levels of
residues being released into the environment. An extractability study on pool
liners and vinyl baby pants showed that leaching would not result in residues
that exceed the 50 ppb maximum limit established for arsenic in drinking
Studies usually required to determine effects on birds, fish and other
nontarget organisms are waived because of OBPA's indoor, industrial use
pattern. Avian and aquatic toxicity information is needed only to assess the
need for precautionary label statements.
Since OBPA is highly corrosive, it would be very highly toxic to birds.
Existing acute oral rat studies confirm that OBPA is highly toxic to
Aquatic studies show that OBPA is very highly toxic to both freshwater and
marine fish, and to freshwater aquatic and marine invertebrates, on an acute
Ecological Effects Risk Assessment
OBPA is an indoor, non-food, industrial use pesticide which is incorporated
into plastics, textiles, adhesives, etc. The Agency does not conduct risk
assessments for nontarget organisms for indoor uses without effluent. Should
residues of OBPA in effluent ever exceed 1.75 ppb, aquatic organisms would be
acutely at risk.
Additional Data Required
EPA is requiring product-specific data, including product chemistry and acute
toxicity studies, as well as rcvised Confidential Statements of Formula and
reviscd labeling for reregistration of pesticide products containing OBPA.
Product Labeling Changes Required
The labels of all registered pesticide products containing OBPA must comply
with EPA's current pesticide labeling requirements. End-use and manufactunng
use products also must bear the following label statement in the Environmental
This pesticide is toxic to fish, aquatic invertebrates, birds, and mammals.
Do not discharge effluent containing this product into lakes, streams, ponds,
estuaries, oceans, or other waters unless in accordance with the requirements
of a National Pollutant Discharge Elimination System (NPDES) pennit and thc
permitting authority has been notified in writing prior to discharge. Do not
discharge effluent containing this product into sewer systems without
previously notifying the local sewaage treatment platn authority. For
guidance contact your state Water Board or Regional Office of EPA
In addition, labels must consistently reflect any potential eye and skin
hazard (Danger, Warning or Caution Signal Words) and recommend appropriate
protective equipment (protective eyeware tgoggles or face shield], waterproof
glaves, long sleeved shirs and long-legged pans, shoes and socks).
The use of currently registered pesticide producs containing OBPA in
accordance with approved labeling will not pose unreasonable risks or adverse
effecs to humans or the ermironment. Therefore. all uses of these products
are eligible for reregistration.
These OBPA products will be reregistered once the required product-specific
data, revised Confidential Statements of Formula and revised labeling are
received and accepted by EPA. Products which contain other active ingredients
in addition to OBPA will be eligible for reregistration only when all of their
other active ingrediens also are determined to be eligible.
For More Information
EPA is requesting public comments on the Reregistration Eligibility
Document (RED) for OBPA 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 (H-7506C),
Office of Pesticide Programs (OPP), US EPA, Washington, DC 20460, telephone
Following the comment period, the OBPA 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 OBPA or about EPA's pesticide reregistration
program, please contact the Special Review and Reregistration Division (H-
7508W), OPP, US EPA, Washington, DC 20460, telephone 703-308-8000. For
information about reregistration of individual products containing OBPA,
please contact Product Manager - Cynthia Giles-Parker, Registration Division
(H-7505C), OPP, US EPA, Washington, DC 20460, telephone 703-305-5540.
For information about the health effects of pesticidcs, or for assistance in
recognizing and managing pesticide poisoning symptoms, please contact the
National Pesticides Telecommunications Network (NPIN). Call toll-free 1-800-
858-7378, between 8:00 am and 6:00 pm Central Tlme, Monday through Friday.