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Aluminum Phosphide - Pesticide Fact Sheet 8/86

                     EPA Pesticide Fact Sheet

Name of Chemical: Aluminum Phosphide
Reason for Issuance:
Date Issued: 0CT 8, 1986

Fact Sheet Number: 69.1

                    1. Description of Chemical

Generic Name: Aluminum Phosphide
Trade Names: Phostoxin, Phosphume, Phostek, etc.
EPA Shaughnessy Code: 066501
Chemical Abstracts Service (CAS) Number: 20859-73-8
Year of Initial Registration:  1978
Pesticide Type: Solid
Chemical Family: Inorganic Phosphides
U.S. and Foreign Producers: Degesch America, Inc.;
Research Products Co., Pestcon Systems, Inc., Bernardo Chemicals.

                 2. Use Patterns and Formulations

Application Sites:  Indoor fumigation of agricultural food commodities, animal
feeds, processed food commodities and non-food commodities (tobacco). Outdoor
fumigation for burrowing rodent and mole control.

Application Rates: 30 tablets or 75 pellets per square foot for fumigation of
mills and warehouses; 1-4 tablets or 5-20 pellets for rodent burrows.

Formulations: Tablets and pellets; powders in bags, envelopes and other types
of containers.

                        3. Science Findings

Summary Science Statement:  The Agency has determined that the registered uses
of this chemical will not generally cause unreasonable adverse effects to
humans or the environment if used in accordance with the approved use
directions and revised precautionary statements prescribed by the registration

Chemical Characteristics:  Solid, dark gray material (granules, or powder);
molecular weight 57.96; material must be protected from moisture in the
atmosphere in air-tight containers; contact of the solid material with
moisture in the air! or with water, or acids release phosphine, a highly toxic

Toxicology Characteristics:  Requirements for acute toxicity data have been
waived because of the well known extreme inhalation toxicity of phosphine gas
which it generates. Accordingly, aluminum phosphide has been placed in
toxicity category I, the highest toxicity category.

No chronic toxicology studies are required with respect to dietary exposure
because there is not potential for dietary exposure (tolerances are set at
limit of detection).

Toxicology studies on phosphine gas are required to assess the margins of
safety for exposed workers and applicators because the Agency does not have
adequate data to determine whether phosphine may cause any long term adverse
effects to humans.

Environmental Characteristics:  Aluminum phosphide reacts with moisture or
water to release phosphine gas, which eventually dissipates into the
atmosphere. The resulting material from the reaction is aluminum hydroxide, a
relatively inert and innocuous material, which is a constituent of clay.

Exposure (monitoring data) and related information are required to help assess
the margins of safety for applicators and workers exposed to phosphine gas.

Ecological Characteristics: Phosphine is a highly toxic gas to a wide range of
living organisms. Indoor uses pose no risk to non-target organisms outside of
the site to be treated. Outdoor end use products (i.e., rodent and mole
control) must bear special precautionary labeling to protect endangered
species. Manufacturing use products must bear environmental hazard statements
for wildlife.

Tolerance Assessment:  Tolerances have been established for raw agricultural
commodities at a level of 0.1 ppm (40 CFR 180.225); processed foods 0.01 ppm
(21 CFR 193.20); and animal feeds 0.1 ppm (40 CFR 561.40). Finished food and
feed must be held 48 hours prior to being offered to the consumer; tobacco
fumigated in hogsheads must be aerated 72 hours.

                              4. Summary of Regulatory Position

Aluminum phosphide will remain a Restricted Use Pesticide due to the extreme
acute toxicity of phosphine gas which is released from the pesticide when it
is exposed to moisture in the air. Therefore, it may by used only by certified
applicators or persons under their supervision.

This amended standard adds several new regulatory requirements to the label:

--For retail sale to and use only by a certified applicator or by persons
trained in accordance with the product manual working under the direct
supervision and in the physical presence of the certified applicator.

--Respiratory protection is not required if the fumigant is applied from
outside of a site such as a railroad car or to fill an automatic dispenser
located outside of a structure. However, if the applicator enters a confined
space to apply the fumigant, respiratory protection is required. Exposure
during application within a confined space may not exceed 0.3 ppm phosphine as
an 8 hour time weighted average (TWA). Engineering controls such as forced air
ventilation are recommended as the primary means of meeting the exposure
standard. Otherwise, an approved respirator must be worn.

--Monitoring must be conducted with a low level detector device to assure that
the exposure standard is not exceeded. If monitoring shows that exposure is
less than the standard, no respirator is required. If more than 0.3 ppm TWA is
encountered, a full face NIOSH/MSHA approved canister respirator is required
up to 15 ppm phosphine. This type of respirator must be available during
fumigation within a confined space. If more than 15 ppm or unknown levels of
phosphine are present, a NOISH/MSHA approved self contained breathing
apparatus (SCBA) is required. SCBA must be available at the site or locally
such as at a fire department or rescue squad.

--After application, no person may be exposed to more than 0.3 ppm phosphine
(maximum concentration). Exposures may occur if the fumigated site leaks into
an adjacent indoor area, during transfer of treated commodity, or during
reentry into an incompletely aerated space.

--All entrances to a fumigated site must be placarded (except for railroad
hopper cars which must be placarded on both sides near the ladders and on the
top hatch where fumigant was applied). A placard may only be removed after the
commodity is completely aerated. Each fumigated site must be monitored and
shown to contain 0.3 ppm or less phosphine in the air space around and in the
mass of the commodity. If more than 0.3 ppm is detected, the placard must be
transferred with the treated commodity. Persons transferring or handling
incompletely aerated commodities must be informed of the presence of phosphine
and adequate measures taken to prevent exposure to more than 0.3 ppm.

--When fumigating from within a confined space or when reentering an
incompletely aerated space, two trained persons must be present.

                         5. Summary of Data Gaps:

90 day inhalation study in rats
Teratogenicity study in one species
Mutagenicity battery
Exposure (monitoring data and related information for major sites)

                         6. Contact person at EPA

Jeff Kempter, PM 32
Disinfectants Branch
Registration Division (TS-767C)
401 M. Street, S.W.
Washington, D.C. 20460
Telephone:  (703) 557-7470

DISCLAIMER:  The information presented in this Pesticide Fact Sheet is for
informational purposes only and may not be used to fulfill data requirements
for pesticide registration and reregistration.