United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-94-023
September 1994
R.E.D. FACTS
Pesticide
Reregistration
Use Profile
2,2-dibromo-3-nitrilo-
propionamide
(DBNPA)
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
reregistration case 3056; 2,2-dibromo-3-nitrilopropionamide or DBNPA.
DBNPA is a biocide used in a variety of industrial processes to control
algae, bacteria, fungi and yeasts. Formulations include tablets and both
solid and liquid soluble concentrates. DBNPA is applied through
shock/slug, initial, intermittent, maintenance, during manufacture and
continuous feed treatments, using metering pumps, drip feed devices and
other types of industrial equipment. A National Pollutant Discharge
Elimination System (NPDES) permit is required for discharges to
waterways.
Regulatory
History
DBNPA was first registered as a pesticide in the U.S. in 1972.
Currently, 44 products are registered that contain this active ingredient.
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Human Health
Assessment
Toxicity
DBNPA is corrosive to the eyes and has been placed in toxicity
category I (the highest of four acute toxicity categories) for this effect. It is
moderately, systemically toxic by oral or inhalation routes (toxicity category
II), and slightly toxic by the dermal route (toxicity category III). Although
classified in toxicity category III for primary dermal irritation, DBNPA can
kill skin tissue in rabbits when administered at high doses for a prolonged
period of time. DBNPA also is a skin sensitizer.
In a subchronic toxicity study using rats, DBNPA caused breathing
difficulty associated with lung or heart disease, as well as weight loss and
several deaths at the higher doses. When applied to the skin of rats in
another subchronic study, DBNPA caused changes in body chemistry and
dermal irritation at the higher doses.
DBNPA is a developmental toxicant in rabbits. It was shown to cause
structural alterations (retarded ossification of several fetal skeleton elements)
at a maternally non-toxic dose level. DBNPA is not mutagenic.
EPA has received several human incident reports in which eye, throat
and respiratory irritation, runny nose and headache resulted from spills or
misuse of DBNPA.
Dietary Exposure
A food additive tolerance, or maximum pesticide residue limit for
processed food, has been established for food grade paper or paperboard
manufactured by processes using DBNPA (please see 21 CFR 176.300).
This tolerance is under the regulatory purview of the Food and Drug
Administration (FDA), and EPA defers to FDA regarding the safety of
dietary exposure to DBNPA.
Occupational and Residential Exposure
The potential for occupational exposure exists, particularly among
those workers or "handlers" loading DBNPA products by open delivery or
pouring methods. Handlers may be at risk for acute or developmental
toxicity effects via dermal or inhalation exposure.
EPA estimated the Margins of Exposure (MOE) to handlers using
open pouring systems and closed systems. All the MOEs are acceptable
except for the scenario in which a handler uses an open pouring method to
add DBNPA to cooling. With appropriate personal protective equipment
(PPE), however, this handler's exposure would be significantly reduced and
the MOE would be acceptable.
Risks to post-application/reentry workers are not anticipated because
their potential for exposure is much less than handlers'. Residential
exposure is not expected since DBNPA has no residential uses.
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Human Risk Assessment
DBNPA is corrosive to the eyes, can kill skin tissue exposed to the
chemical at high levels for a prolonged period of time, and is a
developmental toxicant in rabbits. Several human incidents have been
reported involving acute exposure to DBNPA after spills or misuse.
Handlers of DBNPA may be at risk for acute or developmental
toxicity effects, particularly those using open pouring methods to add the
pesticide to cooling towers. EPA is requiring use of appropriate PPE or a
closed application system through this RED to mitigate these risks to
workers.
Environmental
Assessment
Environmental Fate
Because of its use pattern, DBNPA would not generally contaminate
ground water, but could contaminate surface waters through discharge or
spill. DBNPA generally hydrolyses rapidly in natural waters to many
degradates which continue to degrade rapidly by aerobic and anaerobic
aquatic metabolism. This decreases their threat to surface water
contamination. The primary degradation pathway is through aerobic and
anaerobic metabolism.
Ecological Effects
DBNPA is highly toxic to mammals and birds on an acute oral basis,
but has low toxicity to birds on a dietary basis. The pesticide is moderately
toxic to freshwater fish, estuarine fish and shrimp; moderately to highly
toxic to freshwater crustaceans; and highly to very highly toxic to estuarine
shellfish and larvae. Levels at which acute effects begin for shellfish have
not been established, but are less than the analytical detection limit. Many
effects to aquatic organisms occur within 24 hours of exposure.
Ecological Effects Risk Assessment
DBNPA will be of moderate toxicity to terrestrial mammals and birds
if they are exposed orally to concentrated doses of the pesticide in situations
such as an accidental spill or excessive discharge of the pesticide into a static
pool. Under usual circumstances, however, dietary toxicity to birds is low.
Without any mitigation measures, DBNPA poses a high risk to aquatic
organisms. To mitigate these risks, EPA is requiring secondary biological
treatment of waste water for all uses of DBNPA except use in waste water
treatment systems (since biological degradation readily occurs there,
anyway); in secondary oil recovery systems (where biological treatment is
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Additional Data
Required
Product Labeling
Changes Required
not feasible, but EPA is less concerned about this use pattern due to the
potential for only limited exposure); and in single flow-through cooling
tower systems.
The use of DBNPA in single flow-through cooling tower systems
poses an unacceptable risk to aquatic organisms. Secondary biological
effluent treatment is not practical for this use; thus, the risks it poses to
aquatic organisms cannot be mitigated. Meanwhile, the benefits it affords
are low or non-existent—the amount of DBNPA used for this purpose is
negligible and registered alternatives are less costly. Therefore, the use of
DBNPA in single flow-through cooling tower systems is not eligible for
reregistration, and EPA will take appropriate regulatory action against
DBNPA products labeled for this use.
No additional generic data are required to support current uses of
DBNPA. The Agency is requiring product-specific data including product
chemistry and acute toxicity studies, revised Confidential Statements of
Formula (CSFs) and revised labeling for reregistration.
All DBNPA end-use products must comply with EPA's current
pesticide product labeling requirements, and with the following:
Personal Protective Equipment (PPE), Engineering Controls, and Safety
Requirements
The minimum (baseline) PPE for handlers engaged in open pouring of
DBNPA into cooling towers is: long sleeve shirt, long pants, shoes plus
socks, chemical-resistant gloves, and a chemical-resistant apron.
The following labeling statements are required on all DBNPA end-use
products intended primarily for occupational use:
Application Restrictions:
"Do not apply this product in a way that will contact workers or other
persons, either directly or through drift. Only protected handlers may
be in the area during application."
Engineering Controls:
"When handlers use closed metering systems the handler requirements
may be reduced or modified to long-sleeve shirt, long pants, shoes and
socks."
User Safety Requirements:
"Follow manufacturer's instructions for cleaning/maintaining PPE. If
no such instructions for washables exist, use detergent and hot water.
Keep and wash PPE separately from other laundry."
User Safety Recommendations:
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"Users should wash hands before eating, drinking, chewing gum,
using tobacco, or using the toilet."
"Users should remove clothing immediately if pesticide gets inside.
Then wash thoroughly and put on clean clothing."
"Users should remove PPE immediately after handling this product.
Wash the outside of gloves before removing. As soon as possible,
wash thoroughly and change into clean clothing."
Sensitization Statement:
Required in the "Hazards to Humans (and Domestic Animals)" section
of the Precautionary Statements on labeling of all end-use products:
"This product may cause skin sensitization reactions in some people."
Type of Respirator:
If the acute inhalation toxicity of the end-use product is in category I
or II and, therefore, a respirator is required for pesticide handlers, the
following type of respirator is appropriate to mitigate DBNPA
inhalation concerns:
"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)."
Effluent Discharge Labeling Statement
All DBNPA manufacturing-use or end-use pesticide products that may
be contained in an effluent discharged to the waters of the U.S. or municipal
sewer systems must bear the following statement:
"This product is toxic to fish and invertebrates. 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) permit and
the permitting authority has been notified in writing prior to
discharge. Secondary biological treatment of DBNPA effluent is
required for all uses except for use in secondary oil recovery systems.
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 the EPA."
Most uses of currently registered pesticide products containing DBNPA
Pnnrh i«inn ^n accoi"dance with approved labeling will not pose unreasonable risks or
adverse effects to humans or the environment. Therefore, most DBNPA uses
are eligible for reregi strati on, and pertinent products will be reregistered once
product-specific data, revised Confidential Statements of Formula and revised
labeling are received and accepted by EPA.
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For More
Information
Because the risk to non-target organisms outweighs the potential
benefits associated with the use of DBNPA in single flow-through cooling
towers, this use is ineligible for reregi strati on. EPA will take appropriate
regulatory action against DBNPA products labeled for this use.
EPA is requesting public comments on the Reregi strati on Eligibility
Decision (RED) document for DBNPA 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 DBNPA 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
DBNPA RED, or reregi strati on of individual products containing DBNPA,
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.
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