Fosthietan

This compound is a liquid organophosphorus insecticide. Stay upwind; keep out of low areas. Move containers from fire area if you can do so without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material. Wear positive pressure breathing apparatus and special protective clothing.

Biological Exposure Indices (BEI) [ACGIH] - Acetylcholinesterase activity in red blood cells = 70% of individual's baseline; Butylcholinesterase activity in serum or plasma = 60% of individual's baseline; Sample at end of shift; [TLVs and BEIs]

This compound is a liquid organophosphorus insecticide. Stay upwind; keep out of low areas. Ventilate closed spaces before entering them. Do not touch spilled material; stop leak if you can do so without risk. Use water spray to reduce vapors.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

0.43 [mg/m3]

4.7 [mg/m3]

28 [mg/m3]

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 11(SRC), determined from a water solubility of 5.00X10+4 mg/L(2) and a regression-derived equation(3), indicates that fosthietan is expected to have very high mobility in soil(SRC). Volatilization of fosthietan from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.11X10-11 atm-cu m/mole(SRC), derived from its vapor pressure, 6.45X10-6 mm Hg(4), and water solubility(2). Fosthietan is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Biodegradation data for fosthietan were not available(SRC, 2005).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 11(SRC), determined from a water solubility of 5.00X10+4 mg/L(2) and a regression-derived equation(3), indicates that fosthietan is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 4.11X10-11 atm-cu m/mole(SRC), derived from its vapor pressure, 6.45X10-6 mm Hg(4), and water solubility(2). According to a classification scheme(5), an estimated BCF of 1(SRC), from its water solubility(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data for fosthietan were not available(SRC, 2005).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), fosthietan, which has a vapor pressure of 6.45X10-6 mm Hg at 25 deg(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase fosthietan is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 40 minutes(SRC), calculated from its rate constant of 5.79X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase fosthietan may be removed from the air by wet and dry deposition(SRC).

The Koc of fosthietan is estimated as 11(SRC), using a water solubility of 5.00X10+4 mg/L(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that fosthietan is expected to have very high mobility in soil.

An estimated BCF of 1 was calculated for fosthietan(SRC), using a water solubility of 5.00X10+4 mg/L(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for fosthietan is estimated as 4.11X10-11 atm-cu m/mole(SRC) derived from its vapor pressure, 6.45X10-6 mm Hg(1), and water solubility, 5.00X10+4 mg/L(2). This Henry's Law constant indicates that fosthietan is not expected to volatilize from moist soil or water surfaces(3). Fosthietan is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

The rate constant for the vapor-phase reaction of fosthietan with photochemically-produced hydroxyl radicals has been estimated as 5.79X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 40 minutes at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Measured hydrolysis data for this substance were not available. Phosphate esters such as phosthietan do hydrolyze. However, half-lives for compounds that contain this functional group are typically less than 10 years at pH 7(2).

Fosthietan's former production and use as an insecticide may have resulted in its direct release to the environment. If released to air, a vapor pressure of 6.45X10-6 mm Hg at 25 °C indicates fosthietan will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase fosthietan will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 40 minutes. Particulate-phase fosthietan will be removed from the atmosphere by wet and dry deposition. If released to soil, fosthietan is expected to have very high mobility based upon an estimated Koc of 11. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 4.11X10-11 atm-cu m/mole. Fosthietan is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation data for fostheitan were not available. If released into water, fosthietan is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 1 suggests the potential for bioconcentration in aquatic organisms is low. Measured hydrolysis data for this substance were not available. Phosphate esters such as fosthietan do hydrolyze .However, half-lives for compounds that contain this functional group are typically less than 10 years at pH 7. Occupational exposure and general population exposure should be low or non-existent since fosthietan is no longer produced or used. (SRC)

Emergency and supportive measures. Caution: rescuers and health care providers must take measures to prevent direct contact with the skin or clothing of contaminated victims, because secondary contamination and serious illness may result, especially with potent pesticides and nerve agents. Maintain an open airway and assist ventilation if necessary. Pay careful attention to respiratory muscle weakness; sudden respiratory arrest may occur. If intubation is required, note potential interactions between neuromuscular blockers and cholinesterase inhibitors. Administer supplemental oxygen. Treat hydrocarbon pneumonitis, seizures, and coma if they occur. Observe asymptomatic patients for at least 8-12 hours to rule out delayed-onset symptoms, especially after extensive skin exposureor ingestion of a highly fat-soluble agent. /Organophosphates and carbamates/

Specific drugs and antidotes. Specific treatment includes the antimuscarinic agent atropine and the enzyme reactivator pralidoxime. Give atropine ... repeated frequently as needed. Large cumulative doses of atropine ... may occasionally be required in severe cases. The most clinically important indication for continued atropine administration is persistent wheezing or bronchorrhea. Note: Atropine will reverse muscarinic but not nicotinic effects. Pralidoxime is a specific antidote for organophosphate toxicity, that acts to regenerate the enzyme activity at all affected sites (muscarinic, nicotinic, and probably CNS; however, it does not reactivate plasma cholinesterase). Pralidoxime should be given immediately to reverse muscular weakness and fasciculations... . It is most effective if started within the first 24 hours of the exposure before irreversible phosphorylation of the enzyme, but may still be effective if given late, particularly after exposure to highly lipid soluble compounds. Pralidoxime is not generally recommended for carbamate intoxication, because in such cases the cholinesterase inhibition is spontaneously reversible and short-lived. However, if the exact agent is not identified and the patient has significant toxicity, pralidoxime should be given empirically. /Organophosphates and carbamates/

Decontamination. Note: Rescuers must wear chemical-protective clothing and gloves when handling a grossly contaminated victim. If there is heavy liquid contamination with a solvent such as xylene or toluene, clothing removal and victim decontamination should be carried out outdoors or in a room with high-flow ventilation. 1. Skin. Remove all contaminated clothing and wash exposed areas with soap and water, including the hair and under the nails. Irrigate exposed eyes with copious tepid water or saline. 2. Ingestion. a. Prehospital. Administer activated charcoal, if available. Do not induce vomiting because of the risk of abrupt onset of toxicity. b.Hospital. Administer activated charcoal (cathartics are not necessary if the patient already has diarrhea). Perform gastric lavage for large recent ingestions. /Organophosphates and carbamates/

LD50 Rat oral 5 mg/kg

LD50 Mouse oral 18 mg/kg

LD50 Rat male oral 4.7 to 7.7 mg/kg /Technical Nem-A-Tak/

LD50 Rat female oral 6.9 mg/kg /Technical Nem-A-Tak/

For more Non-Human Toxicity Values (Complete) data for FOSTHIETAN (11 total), please visit the HSDB record page.

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Fosthietan is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 500 lbs.