I have previously posted about particulate air pollutants in the workplace:
Confused About Dust, Particulates and Fumes in the Workplace? Part 1: Dust and Particulate Matter
I’ll continue the theme of potentially harmful air pollutants with a look at volatile compounds.
Let’s start by defining what we mean by volatile compounds.
If you remember your high school chemistry classes, volatile compound are those compounds that vaporize, i.e., phase shift from liquid to gas. Compounds can vaporize via evaporation (e.g., water evaporating from a puddle that dries up following a rain) and boiling (e.g., steam produced by a kettle on the stove – leave it too long and all the water will have fully volatilized into the air leaving you with a black bottomed kettle!). The propensity of a compound to volatilize is a function of the vapor pressure of the compound, for instance at a given temperature, a compound with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.
From an occupational health and safety perspective, most people think of volatile organic compounds (VOCs), but, there are also many volatile inorganic compounds (VICs) that pose hazards for workers and the environment. I think that it is well worth being aware of both types of volatile compounds. As this is a reasonably complex topic I will discuss volatile compounds in two separate blog posts:
Volatile Compounds in the Workplace: Part 1 VOCs (this blog post)
Volatile Compounds in the Workplace: Part 2 VICs
For each post. I will describe the most common compounds that one might expect to encounter in the workplace, list sources that may lead to elevated levels in the workplace, discuss regulatory issues, describe potential health concerns, and offer suggestions to protect your workers from these hazards.
What are Volatile Organic Compounds?
I think this is obvious, these are organic compounds (compounds that contain molecules of carbon) and easily vaporize, i.e., have a relatively high vapor pressure at room temperature so they will form a gas at room temperature.
There are literally hundreds (if not thousands) of specific VOCs – examples of a few of the more common ones that might be encountered in the workplace are BTEX (benzene, toluene, ethylbenzene, xylene), methylene chloride, acetone, and formaldehyde.
Sources of VOCs in the Workplace
Volatile organic compounds (VOCs) are ubiquitous and arise from both natural and anthropogenic sources.
Natural sources are primarily from plants to a lesser extent from forest fires and from oceans; we will not discuss these natural sources here, but if interested see IPCC for more details.
Anthropogenic sources of VOCs arise from burning of fossil fuels and waste and from use of solvents, paints, glues, dry-cleaning fluids, etc. They can be found essentially everywhere in the workplace. For instance, we are all aware of the “new office smell”. This is from VOCs being emitted into the office environment from sources such as:
• Caulks, sealants, and coatings
• Adhesives
• Paints, varnishes and/or stains
• Wall coverings
• Cleaning agents
• Fuels and combustion products
• Carpeting
• Vinyl flooring
• Fabric materials & furnishings
While these sources can be a problem for some sensitive people, the main issue with VOCs are from releases from work areas, particularly within enclosed and improperly ventilated spaces. This includes areas with activities or processes such as painting, cleaning with solvents, gluing, printing, fuel storage and filling, dry cleaning, refining petrochemicals, chemical manufacturing, burning hydrocarbons and waste, etc.
One other source that needs mentioning, and in my experience one that few HSE professionals in developing countries are aware of, is the issue of VOC release into enclosed spaces from leakage of undergoing fuel tanks or other sources of subsurface VOC contamination. For instance, when diesel spills or leaks into the soils and infiltrates into shallow groundwater, then there is potential for VOCs to migrate via the groundwater pathway some distance from the source and volatilize upward through the soils. This can lead to infiltration of VOCs into buildings or enclosed facilities – a hazardous situation to inhabitants or users of those facilities, particularly if the VOCs contain carcinogens such as benzene.
VOC Regulations
Regulations for VOCs in the workplace vary widely from country to country. Many developing countries have yet to promulgate legislation for VOC levels in the workplace. Others only regulate levels of Total VOCs. And, some also regulate levels of specific VOCs. There may also be differences between regulated levels in the workplace vs ambient levels at the property boundary. You will need to fully understand your local regulatory requirements. Check out my blog post on preparing your own HSE legal register and compliance auditing spreadsheet as a means to help you identify the legal requirements for your facility.
Hazards of VOC Exposure
The primary exposure route for VOCs is from inhalation of VOCs in air, albeit dermal exposure pathways should also be considered for some VOCs.
Potential health effects of VOC exposure will vary greatly according to the nature of the compound and the level and duration of exposure. Some VOC compounds are essentially harmless and others are highly toxic. The EEB’s risctox database lists well over 400 different VOCs. Short term exposure may cause conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnoea, nausea, emesis, epitasis, fatigue, dizziness. While long term exposure to volatile organic compounds may cause lesions to the liver, kidneys and central nervous system.
Control of VOC Exposure
The HSE professional much understand the hazards of the specific VOCs that their workers may be exposed to and provide information and training specific to the VOCs at their site. In general, control systems include appropriate ventilation and exhaust systems combined with appropriate PPE: respiratory protection, proper clothing, gloves, eye protection, etc.
In Part 2 I’ll provide some suggestions as to how to evaluate whether or not you may have a problem with volatile compounds at your facility.
Of course, if you have any concerns about VOCs or any other air quality issues at your facility and/or need assistance in designing and/or carrying out a VOC assessment and/or exposure study, feel free to contact us. We will most certainly be pleased to help.
Thanks for reading. Keep safe. Be healthy. Respect your environment.
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Next Week’s Blog Topic: Volatile Compounds the Workplace: Part 2 VICs
Photo Credits: VOC spills photo courtesy of Redlog Environmental Ltd.
