Volatile organic compounds (VOCs) are carbon-based chemicals that evaporate easily at room temperature, releasing vapors from paints, solvents, fuels and cleaners that can harm health and fuel fires.
Volatile organic compounds (VOCs) are carbon-based chemicals that evaporate readily at normal room temperature. Because they have a high vapor pressure and a low boiling point, they move easily from a liquid or solid into the air, where workers can breathe them in. Common workplace sources include paints, coatings, adhesives, degreasers, fuels, printing inks, cleaning products and many industrial solvents.
The term has more than one definition depending on who is using it. For outdoor air pollution, the US Environmental Protection Agency (EPA) defines VOCs in 40 CFR 51.100(s) as any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates and ammonium carbonate, that participates in atmospheric photochemical reactions. In other words, the EPA definition is about chemicals that help form ground-level ozone. Compounds that the EPA has found to have negligible photochemical reactivity, such as methane, ethane and acetone, are excluded from that regulatory definition. In the European Union, the Industrial Emissions Directive (2010/75/EU) instead defines a VOC by volatility: an organic compound with a vapor pressure of 0.01 kPa or more at 293.15 K (20°C).
For workplace safety, these regulatory definitions matter less than what a specific chemical does to people. A solvent can be exempt from the EPA's VOC definition and still be highly flammable or toxic. Acetone is a good example: it is exempt for air quality purposes, but it has an OSHA exposure limit and a flash point of 0°F.
The EPA lists the following health effects linked to VOC exposure, which vary widely by chemical and concentration:
Many VOCs are also absorbed through the skin, which is one reason organic solvent exposure is treated as both an inhalation and a skin hazard.
Most VOCs used as solvents and fuels are flammable. Their vapors can build up in poorly ventilated areas and reach the lower explosive limit (LEL), where a spark, hot surface or open flame can ignite them. Many VOC vapors are heavier than air and can collect in pits, sumps and low areas.
The EPA reports that concentrations of many VOCs are consistently higher indoors, up to ten times higher, than outdoors. Offices, labs, print rooms and buildings with fresh paint, new furnishings or heavy cleaning product use can all have elevated levels.
OSHA does not set a single limit for "VOCs" as a group. Instead, it sets a permissible exposure limit (PEL) for individual chemicals. Some of the most common VOCs have their own detailed standards:
Many other VOCs are covered by the air contaminant tables in 29 CFR 1910.1000. For example, toluene has a PEL of 200 ppm TWA with a 300 ppm ceiling in Table Z-2, and acetone has a PEL of 1,000 ppm TWA in Table Z-1. Under the Hazard Communication Standard, 29 CFR 1910.1200, the safety data sheet (SDS) for each product lists its hazardous ingredients, exposure limits and physical properties such as vapor pressure and flash point.
A cabinet shop finished its products with a solvent-based lacquer in an open area of the plant. Workers in nearby areas complained of headaches and a strong odor by mid-afternoon. Air sampling found that toluene and xylene exposures for the finishing crew were below their PELs, but close enough to be a concern, and that the vapor was drifting into the assembly area.
The shop moved finishing into a spray booth with exhaust ventilation, switched its sealer coat to a waterborne product and started keeping solvent containers closed between uses. It also removed ignition sources from the finishing area. Follow-up sampling showed exposures well below the limits, and the odor complaints stopped.
No. OSHA sets limits for individual chemicals, not for VOCs as a group. Check the SDS and OSHA's standards for each chemical present.
Not automatically. "Low-VOC" usually refers to air quality rules, and some exempt solvents are still flammable or toxic. Review the SDS before assuming a product is safer.
No. Some VOCs have a strong odor at low levels, while others can be harmful before they are noticeable, and people get used to odors quickly. Use air monitoring instead.
It shows the combined level of compounds a detector responds to. It helps find sources and trends, but chemical-specific sampling is needed to check compliance with exposure limits.
No. Outdoor work such as fueling, tank cleaning and road paving can also produce high VOC exposures, especially in enclosed or low-lying areas with little air movement.
Part of SafetyIQ's EHS glossary: plain-English definitions of workplace health and safety terms.
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