It is estimated that up to 1.3 million workers are exposed to polycyclic aromatic hydrocarbons (PAHs) in the EU. PAHs are classified as Group 1 carcinogen by IARC, meaning they are seen as a definite cause of cancer.

Many PAHs are classified as category 1A or 1B carcinogen according to CLP regulation, meaning that the substances are a definite cause of cancer or may cause cancer in humans. PAHs can be swallowed, inhaled, or in some cases, pass through the skin. Long-term exposure can cause lung and skin cancer.

Where risks occur

Workers in industries or trades using or producing coal or coal products are at highest risk for PAH exposure. These workers include asphalt workers, coal-gas workers, fishermen (coal tar on nets), graphite electrode workers, mechanics (auto and diesel engine), road (pavement) workers and tire and rubber manufacturing workers. Also, firefighting, waste incineration, smokehouses, cooking, crematoria, chimney sweeping, wood preservation and soil remediation are associated with unintentional generation of PAHs.

More about the substance

PAHs are a class of numerous chemicals that occur naturally in coal, crude oil, and gasoline. They are also formed through high temperature processes that result from incomplete combustion or pyrolysis of organic materials such as coal, oil, gas, wood, garbage and tobacco. PAHs generated from these sources can bind to or form small particles in the air. High-temperature cooking will form PAHs in meat and in other foods. Cigarette smoke contains many PAHs.

How symptoms can affect you

PAHs have low acute toxicity. Acute effects attributed to exposure to PAHs are probably caused by other agents. Long-term occupational exposure to PAHs can affect multiple systems of the body. It can affect the respiratory system (decrease in lung function, chest pain, irritation of the airways and lung cancer), gastrointestinal system (including gastrointestinal cancer), skin (burns and warts on sun-exposed areas that may develop into cancer), and eyes (eye irritation). It may also be a cause of other types of cancer such as leukemia, liver and bladder cancer.

The latency period between exposure and PAHs related cancer varies from 5 to 20 years, depending on the different types of cancer.

What you can do

Periodically carry out representative exposure measurements so that it is known when and where further risk reduction measures should be taken. Make workers continuously aware of the effects of exposure and encourage them to report early symptoms. Best solution is to control exposure by elimination or substitution. However, since PAHs originate from burning processes it is not easy to eliminate or substitute this substance. The fume should be minimized as close as possible to the source by re-designing the work and reconsidering the techniques and materials used, for instance an extracted welding torch. If that does not work, the emission should be controlled in the close vicinity of the source, for example by using local exhaust ventilation systems. Personal protective equipment should only be used as a last resort, after the possible technical solutions have been exhausted. If being used, make sure the right personal protective equipment is at hand. For PAHs, it is also possible to monitor body burden by performing biomonitoring if applicable according to national legislation.

References: CDC, IARC, IA study report