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Comment On Cylinderized Phosphine Gas Products:

Cylinderized phosphine gas should not be subject to ecological and environmental fate risk 

assessment because use in burrows is not permitted. Aquatic and terrestrial exposure to 

cylinderized phosphine gas is not expected. None of the reported incidents with phosphine gas 

involved ECO2FUME® or VAPORPH3OS®.

EFED response:

Aquatic and terrestrial exposure is expected for any phosphine product, including cylinderized 

gas products, once phosphine is released from fumigated structures. Limited aquatic exposure is 

expected as noted in the problem formulation. Therefore, EFED is mainly concerned with 

terrestrial exposures.

Comments on Ecological Effects Data Gaps:

The three ecotoxicology studies are not needed (avian acute inhalation, honey bee acute 

inhalation, and terrestrial plant vapor phase study). During aeration, phosphine will be diluted 

and will degrade rapidly in the atmosphere. Monitoring data around fumigation sites indicates 

that phosphine air concentrations are low, transient (less than two hours), and rarely present more 

than 3-15 feet from the fumigated structure. Monitoring that is required for protection of 

workers and bystanders is equally protective of non-target plants and animals. The requirement 

for terrestrial plant toxicity is not relevant since phosphine below the soil surface is quickly 

absorbed and degraded. The likelihood of avian and honeybee exposure to phosphine gas in the 

environment at an atmospheric concentration high enough to produce toxicity is almost nonexistent. 

EFED response:

Monitoring data as well as modeling predictions are used to estimate exposure to phosphine gas

(i.e., what concentration of phosphine gas is expected around fumigated structures). Such data 

are useful for worker protection only because the concentration/duration of exposure that is 

harmful to human health is known from other studies (effects data) that can be compared to the 

monitoring data. The requested studies generate effects data for birds, insects, and plants for 

comparison with the monitoring data and modeling predictions. Birds, insects, and terrestrial 

plants could be exposed to peak concentrations of phosphine emitted around the exterior of 

fumigated structures (also plant roots in treated burrows). Phosphine gas is extremely toxic to 

animals by inhalation and can cause harmful effects even over short exposure periods. 

Therefore, EFED considers these effects data to have high value in reducing uncertainty of risk. 

Comments on Use and Usage Information:

Under Use Sites, information for phosphine has not been fully included. In addition to the uses

listed, Cytec's products are permitted to be used on a variety of stored fresh fruit and vegetable

commodities.
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In the Summary of Usage, although it is true that use of phosphine products has increased as

methyl bromide has been phased out and the use of cylinderized phosphine has increased

because it allows for better control of targeted fumigations, the figures produced by BEAD do

not appear to be correct. Table 3 of the supporting BEAD chemical profile in the docket lists use 

in 2009 at 164,241lb phosphine from aluminum phosphide use, 7,9571b phosphine from

magnesium phosphide use and 263,667 lb phosphine, presumably from use of ECO2FUME and

VAPORPHOS. These reported values suggest that 1.6x more cylinderized phosphine is sold than 

aluminum and magnesium phosphide combined. As reported in the information summary

provided to EPA on June 3, 2013, estimated phosphine from Cytec's cylinderized phosphine

products was much less than that amount. Perhaps DPR inadvertently counted a cylinder of

ECO2FUME as 100% phosphine when in fact it consists of 2% phosphine on a w/w basis.

The formulation type should be corrected to read "Phosphine is formulated and cylinderized as a 

liquid pressurized gas”.

EFED response:

EFED will make these corrections in the ecological risk assessment document, as warranted. The 

Agency will verify the usage corrections in paragraph two of the registrant comments (above)

and make corrections to the BEAD chemical profile if appropriate.