2-Butanethiol

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide. /Butyl mercaptan/

... Materials which are toxic as stored or which can decompose into toxic components ... should be stored in a cool, well ventilated place, out of the direct rays of the sun, away from areas of high fire hazard, and should be periodically inspected. Incompatible materials should be isolated ...

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.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

Generally process from which mercaptan vapor is liable to be evolved should as far as practicable be enclosed, and exhaust ventilation should be provided to prevent vapors from diffusing into atmosphere of workroom. /mercaptans/

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to disperse vapors and dilute standing pools of liquid. /Butyl mercaptan/

Personnel protection: Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. ... /Butyl mercaptan/

For more Preventive Measures (Complete) data for SEC-BUTYL MERCAPTAN (6 total), please visit the HSDB record page.

15 [mg/m3]

170 [mg/m3]

1000 [mg/m3]

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 84(SRC), determined from a water solubility of 1.32X10+3 mg/L(2) and a regression-derived equation(3), indicates that sec-butyl mercaptan is expected to have high mobility in soil(SRC). Volatilization of sec-butyl mercaptan from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 7.3X10-3 atm-cu m/mole(SRC), derived from its extrapolated vapor pressure, 81 mm Hg(4), and water solubility(2). sec-Butyl mercaptan is expected to volatilize from dry soil surfaces(SRC) based upon its extrapolated vapor pressure(4). Biodegradation data were not available(SRC, 2005).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 84(SRC), determined from a water solubility of 1.32X10+3 mg/L(2) and a regression-derived equation(3), indicates that sec-butyl mercaptan is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 7.3X10-3 atm-cu m/mole(SRC), derived from its extrapolated vapor pressure, 81 mm Hg(4), and water solubility(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3 hours and 4 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 11(SRC), from its water solubility(2) and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data were not available(SRC, 2005).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), sec-butyl mercaptan, which has an extrapolated vapor pressure of 81 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase sec-butyl mercaptan 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 7 hours(SRC), calculated from its rate constant of 4.0X10-11 cu cm/molecule-sec at 25 °C(3). sec-Butyl mercaptan does not absorb light at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight.

The Koc of sec-butyl mercaptan is estimated as 84(SRC), using a water solubility of 1.32X10+3 mg/L(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that sec-butyl mercaptan is expected to have high mobility in soil.

/SIGNS AND SYMPTOMS/ Strong, offensive smell of mercaptans can cause headache and nausea. High concentration of their vapors in atmosphere can produce unconsciousness with cyanosis, a sense of coldness at the extremities and quickening of pulse. ... Pulmonary edema /is also observed/. /Mercaptans/

An estimated BCF of 11 was calculated for sec-butyl mercaptan(SRC), using a water solubility of 1.32X10+3 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 sec-butyl mercaptan is estimated as 7.3X10-3 atm-cu m/mole(SRC) derived from its vapor pressure, 80.7 mm Hg(1), and water solubility, 1.32X10+3 mg/L(2). This Henry's Law constant indicates that sec-butyl mercaptan is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 3 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 4 days(SRC). sec-Butyl mercaptan is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

/LABORATORY ANIMALS: Acute Exposure/ /In rats/, ... symptoms after oral exposure included ataxia and body weight loss.

/LABORATORY ANIMALS: Acute Exposure/ Instillation into rabbit eyes caused acute pain and moderate conjunctival irritation for 2 days.

/LABORATORY ANIMALS: Neurotoxicity/ Acute neurotoxic effects reported in animals include cholinesterase inhibition. /From table/

/OTHER TOXICITY INFORMATION/ ... /Investigators/ observed that at concentrations near the intraperitoneal LD50 in the rat CNS effects and cholinesterase inhibition occur.

The rate constant for the reaction of sec-butyl mercaptan with hydroxyl radicals has been experimentally determined to be 3.8X10-11 to 4.0X10-11 cu cm/molecule-sec at 25 °C(1-3). This corresponds to an atmospheric half-life range of about 7 to 11 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1-3). sec-Butyl mercaptan is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(4). sec-Butyl mercaptan does not absorb light at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight.

NIOSH (NOES Survey 1981-1983) has statistically estimated that 4,715 workers are potentially exposed to sec-butyl mercaptan in the US(1). Occupational exposure to sec-butyl mercaptan may occur through inhalation and dermal contact with this compound at workplaces where sec-butyl mercaptan is produced or used(SRC). Use data suggest that the general population may be exposed to sec-butyl mercaptan via inhalation of ambient air in the vicinity of natural gas refineries and operations due to use as a natural gas odorant(SRC).

sec-Butyl mercaptan's production and use as a natural gas odorant may result in its release to the environment through various waste streams. If released to air, an extrapolated vapor pressure of 81 mm Hg at 25 °C indicates sec-butyl mercaptan will exist solely as a vapor in the ambient atmosphere. Vapor-phase sec-butyl mercaptan 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 7 hours. sec-Butyl mercaptan does not absorb light at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, sec-butyl mercaptan is expected to have high mobility based upon an estimated Koc of 84. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 7.3X10-3 atm-cu m/mole. Biodegradation data were not available. If released into water, sec-butyl mercaptan is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3 hours and 4 days, respectively. An estimated BCF of 11 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to sec-butyl mercaptan may occur through inhalation and dermal contact with this compound at workplaces where sec-butyl mercaptan is produced or used. Use data suggest that the general population may be exposed to sec-butyl mercaptan via inhalation of ambient air in the vicinity of natural gas refineries and operations due to use as a natural gas odorant. (SRC)