Unttad Statu
Environmental Pro tact ion
Agancy
Offica of Paaticidai and Toxic Sufaatancaa
Offica of Pact kid a Program* (TS-766C)
VWiington. DC 20460
S^o/PS-?? -O/S
vvEPA Pesticide
Fact Sheet
Name of Chemical: auiunum and magnesium phosphide
Reason for Issuance: amendment to registration standard
Date Issued: FEB 2 0 1987
Fact Sheet Number: lis
1.	Description of Chemicals
Generic Names: Aluminum Phosphide, Magnesium Phosphide
Trade Names: Phostoxin, Gastoxin, Quick Phos, Detia, etc.
EPA Shaughnessy Codes: 066501 (aluminum phosphide), 066504
(magnesium phosphide)
Chemical Abstracts Service (CAS) Numbers: 20859-73-8 and
12057-74-8
Year of Initial Registration: 1978 and 1979
Pesticide Type: Solid
Chemical Family: Inorganic Phosphides
U. S. Registrants: Degesch America, Inc.; Research Pro-
ducts Co.; Pestcon Systems, Inc.; Bernardo Chemicals
Ltd., Inc.; Phos-Fume Chemical Co.; Woodbury Chemical
Co, of Missouri; Alpha Chemical Co.
2.	Use Patterns and Formulations
Application Sites: Indoor fumigation of agricultural
food commodities, animal feeds, processed food commodi-
ties and non-food commodities (tobacco). Outdoor fumi-
gation 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 standard.

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Chemical Characteristics: Solid, dark gray material (granules
or powder); molecular weight of aluminum phosphide is 57.96;
molecular weight of magnesium phosphide is 134.779; 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 gas.
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 and magnesium phosphide have 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. These studies include 90 day inhalation, teratog-
enicity and mutagenicity testing.
Environmental Characteristics: Aluminum and magnesium phos-
phide react with moisture or water to release phosphine gas,
whi.ch. eventually dissipates into the atmosphere. The result-
ing material from the reaction is aluminum or magnesium
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 and 180.375); processed foods 0.01 ppm (21 CFR
193.20 and 193.225); and animal feeds 0.1 ppm (40 CFR 561.40
and 561.268). 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.

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Summary of Regulatory Position
—Aluminum and magnesium phosphide are Restricted use
Pesticides due to the extreme acute toxicity of phosphine
gas which is released from the pesticide when it is
exposed to moisture in the air. They may by used 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.
Physical presence means that the certified applicator
must be available on the site or on the premises.
—Respiratory protection is not required if the fumigant
is applied from outside of an enclosed indoor area.
However, if the applicator enters an enclosed indoor area
to apply the fumigant, a NIOSH/MSHA approved canister
respirator is required at the site. Exposure during
application 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.
A sufficient number of samples should be taken in places
where worker exposure is likely to occur. It is recommended
that the applicator or employer document exposure readings
in an operation log or manual for each fumigation site.
Once exposures have been adequately characterized for a
particular site, subsequent monitoring is not routinely
required for each aplication. However, spot checks should
be made, especially if conditions significantly change
or if a garlic odor is detected.
—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 an enclosed indoor area. If more than 15 ppm or
unknown levels of phosphine are present, a NIOSH/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). Examples
are: if the fumigated site leaks into an adjacent indoor
area, during transfer of treated commodity or during
reentry into an incompletely aerated space.

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—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.
To determine whether aeration is complete, each fumi-
gated site or vehicle must be monitored and shown to
contain 0.3 ppm or less phosphine gas in the air
space around and, when feasible, 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.
—At least two trained persons must be present when the
product is applied from within a space to be fumigated
or during reentry into a fumigated or partially aerated
space.
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.	Implementation of Labeling:
March 1, 1987 -- Registrants submit revised labeling.
March 15, 1987 — EPA returns approved new product manuals
and labels.
May 31, 1987 — Cases of product entering commerce after
this date must contain a new EPA approved product manual.
A stamp or similar notice on the outside of the case
will read:
"The use of aluminum (or magnesium) phosphide is required
to be used in accordance with the procedures and safeguards
described in the product manual dated 	. A copy
of that manual is enclosed in this case. You are required
to review this manual before using this pesticide. If you
are purchasing less than a full case, your retailer or
distributor must provide you, without charge, a copy of
this manual. Notice to Retailers -- Each purchaser of
this pesticide, whether by the case lot or less than
a case lot, must receive a copy of the manual described
in this notice."

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The phrase "entering commerce" means that registrants
may not release for shipment, distribute, sell offer
for sale, hold for sale, ship, deliver for shipment,
or receive and (having so received) deliver or offer
to deliver, to any person products which do not meet
these requirements after May 31, 1987.
January 31, 1988 — All pesticide product containers
must bear an EPA approved label which complies with the
Registration Standard. In addition, an approved
product manual must be in each case. After this date
registrants may not release for shipment or other
persons may not distribute, sell, offer for sale, hold
for sale, ship, deliver for shipment, or receive and
(having so received) deliver or offer to deliver, to
any person products which do not meet these requirements.
7. 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 regis-
tration and reregistration.

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