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

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

TIME-WEIGHTED AVERAGE (TLV-TWA) : 100 ppm - Carcinogenicity Designation A4

SHORT-TERM EXPOSURE LIMIT (TLV-STEL) : 150 ppm - Carcinogenicity Designation A4

TLV BASIS - CRITICAL EFFECT(S) : Irritation

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

What are the fire and explosion dangers associated with xylene?

Flammable liquid. It can release vapours that form explosive mixtures with air at, or above, 17?C (about 63?F). The liquid can accumulate static charge when it flows through hoses or is agitated. Xylene vapour can be ignited by a static charge. 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. It can float on water and may travel to distant locations and/or spread fire. During a fire, irritating/toxic gases may be generated. It can accumulate in confined spaces, resulting in a toxicity and flammability hazard. Containers may explode in heat of fire.

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

Normally stable to heat, light and air.

Are there any conditions to avoid when using xylene?

Static discharge, sparks, open flames, heat, other ignition sources.

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

1 ppm (detection); 20 ppm (detection); 40 ppm (recognition).

Is the odour of xylene reliable as a warning property?

GOOD - TLV is more than 10 times the odour threshold.

How can I work with xylene safely?

This material is a FLAMMABLE AND VERY TOXIC liquid (POSSIBLE REPRODUCTIVE 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 the potential hazards.

Eliminate all ignition sources (e.g. sparks, open flames, hot surfaces). Immediately report leaks, spills or ventilation failures. Unprotected persons should avoid all contact with this chemical including contaminated equipment. Consider using closed handling systems for processes involving this material. If a closed handling system is not possible use in the 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.

Keep away from heat. Post NO SMOKING signs. It is very important to keep areas where this material is used clear of other materials which can burn. Liquid can accumulate charge. Increase conductivity with additive designed for that purpose, reduce flowrate 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. 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. Keep aisles and exits free of obstruction. For large scale operations, consider the installation of leak and fire detection equipment along with a suitable, automatic fire suppression system.

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.

Inspect containers for leaks before handling. Stand upwind of all opening, pouring and mixing operations. 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. Assume that empty containers may contain hazardous residues.

Follow handling precautions on Material Safety Data Sheet. Practice good housekeeping. Maintain handling equipment in good, operating condition. 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.

Use a non-sparking, grounded ventilation system separate from other exhaust ventilation systems. Exhaust directly to the outside, taking necessary precautions for environmental protection. When there is large scale use of this material, consider using a closed handling system including local exhaust ventilation with process enclosure. Supply sufficient replacement air to make up for air removed by exhaust systems.

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Document last updated on January 15, 2003

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