• What is the American Conference of Governmental Industrial Hygienists (ACGIH) recommended exposure limit for toluene?
• What are the fire and explosion dangers associated with toluene?
• Is toluene stable when exposed to air, moisture, or heat?
• Are there any conditions to avoid when using toluene?
• Does toluene have an odour threshold (at what level can I smell it)?
• Is the odour of toluene reliable as a warning property?
• How can I work with toluene safely?
• What can be done to control hazardous conditions?

What is the American Conference of Governmental Industrial Hygienists (ACGIH) recommended exposure limit for toluene?

TIME-WEIGHTED AVERAGE (TLV-TWA): 20 ppm - Carcinogenicity Designation A4

TLV BASIS - CRITICAL EFFECT(S) : Visual impairment; female reproductive damage; pregnancy loss

CARCINOGENICITY DESIGNATION A4 - Not Classifiable as a Human Carcinogen: Inadequate data on which to classify the substance as a human and/or animal carcinogen.

BIOLOGICAL EXPOSURE INDICES (BEIs): The ACGIH has adopted a BEI for this chemical. BEIs provide an indicated of worker exposure by measuring the chemical or its breakdown products in the body or by measuring biochemical changes resulting from exposure to the chemical. Consult the BEI documentation for further information.

NOTE: In many Canadian jurisdictions, exposure limits are similar to the ACGIH TLVs. Since the manner in which exposure limits are established, interpreted, and implemented can vary, obtain detailed information from the appropriate government agency in each jurisdiction.

What are the fire and explosion dangers associated with toluene?

Toluene is a FLAMMABLE LIQUID. It can release vapours that form explosive mixtures with air at, or above, 4 deg C. The vapour is heavier than air and may travel a considerable distance to a source of ignition and flash back to a leak or open container. The liquid can float on water and may travel to distant locations and/or spread fire. Toluene can accumulate static charge by flow or agitation due its low electrical conductivity. Vapour in the flammable range can be ignited readily by a static discharge of sufficient energy.

Is toluene stable when exposed to air, moisture, or heat?

Toluene is normally stable.

Are there any conditions to avoid when using toluene?

Electrostatic discharge, sparks, open flames, heat and other ignition sources.

Does toluene have an odour threshold (at what level can I smell it)?

There is a wide variation in values: 0.16 - 37 ppm (detection); 1.9 - 69 ppm (recognition).

Is the odour of toluene reliable as a warning property?

NOT RELIABLE: Wide variation in odour threshold values. Smell may not be noticed after short exposure. Very short exposure (3-5 minutes) to the vapour has caused slight eye irritation at 300 ppm.

How can I work with toluene safely?

Toluene is a FLAMMABLE LIQUID, a REPRODUCTIVE HAZARD and a SKIN IRRITANT. It is also a CONFINED SPACE HAZARD. Before handling, it is very important that engineering controls are operating and that protective equipment requirements are being followed. People working with this chemical should be properly trained regarding its hazards and its safe use. Maintenance and emergency personnel should be advised of potential hazards.

If toluene is released, immediately evacuate the area until the severity of the release can be determined. Immediately report leaks, spills or ventilation failures. Eliminate all ignition sources (e.g. sparks, open flames, hot surfaces). Keep away from heat. Use in smallest possible amounts in a well ventilated area separate from the storage area. Avoid generating vapours or mists. Prevent the release of vapours and mists into the workplace air.

Post NO SMOKING signs. Liquid can accumulate charge. Increase conductivity with additive designed for that purpose, reduce flow rate in transfer operations, increase time the liquid remains in transfer piping and/or handle at lower temperature. Electrically ground all drums, transfer vessels, hoses and piping. Ground clips must contact bare metal. When dispensing in other than a closed system, ensure dispensing container is bonded to receiving transfer equipment and container.

Never perform any welding, cutting, soldering, drilling or other hot work on an empty vessel, container or piping until all liquid and vapours have been cleared. It is very important to keep areas where this material is used clear of other materials which can burn. Keep aisles and exits free of obstruction.

To reduce the fire/explosion hazard, consider the use of an inert gas in the container or storage vessel. Use non-sparking ventilation systems, approved explosion-proof equipment and intrinsically safe electrical systems in areas of use. For large scale operations, consider the installation of leak and fire detection equipment along with a suitable, automatic fire suppression system.

Wear appropriate personal protective equipment, if necessary, to avoid skin contact with this chemical and any contaminated equipment.

Do not use with incompatible materials such as strong oxidizing agents (e.g. peroxides, nitrates and perchlorates). These can increase the risk of fire and explosion.

To avoid splashing, carefully dispense into sturdy containers made of compatible materials. Never transfer liquids by pressurizing the original shipping containers with air or inert gas. Do not dispense in storage area unless dispensing area is segregated by fire-resistant construction. Only use portable containers and dispensing equipment (faucet, pump, drip can) approved for flammable liquids. Never return contaminated material to its original container. Label containers.

Keep containers closed when not in use. Avoid damaging containers. Empty containers may contain hazardous residues.

If toluene is being used in a confined space, all confined space safety procedures should be carefully followed. Continuous air monitoring will probably be necessary to determine if there is adequate ventilation.

Follow handling precautions on Material Safety Data Sheet. Practice good housekeeping. Maintain handling equipment. Comply with applicable regulations.

What can be done to control hazardous conditions?

Engineering methods to control hazardous conditions are preferred. Methods include mechanical ventilation (dilution and local exhaust), process or personnel enclosure, control of process conditions, and process modification (e.g. substitution of a less hazardous material). Administrative controls and personal protective equipment may also be required. Local exhaust ventilation with or without process enclosure may be necessary. Use a non- sparking, grounded ventilation system separate from other exhaust ventilation systems. Exhaust directly to the outside, taking necessary precautions for environmental protection.

To reduce the fire/explosion hazard, consider the use of an inert gas in the container or storage vessel. Use approved explosion-proof equipment and intrinsically safe electrical systems in areas of use.

For large scale operations, consider the installation of leak and fire detection equipment along with a suitable, automatic fire suppression system. Supply sufficient replacement air to make up for air removed by exhaust systems.

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Document last updated on December 5, 2008

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