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Hydrocarbon releases - acute health effects

Hydrocarbon releases pose more than just the risk of fire and explosion. Personnel who are in an area where there are such releases can be exposed to serious health hazards.


In 2003, two persons on the Brent A facility in the British sector died after having inhaled high concentrations of hydrocarbons. Subsequent to this incident, the Petroleum Safety Authority Norway (PSA) has conducted a series of audits and has become aware that the industry has insufficient knowledge concerning the acute health effects of hydrocarbon releases.

The Health and Safety Executive in the U.K. (HSE) has published a safety notice (4/2004) describing various types of acute health effects and recommended measures.

Exposure to hydrocarbon gas can cause a narcotic effect in concentrations lower than those that represent an explosion or asphyxiation hazard. Tests have indicated that the narcotic effect can occur at levels down to 20-30% of the low explosion limit (LEL), but this will depend on the composition of the gas, duration of exposure and the type of measuring instrument. The potential for narcotic effect increases as the molecular weight rises, which means that the risk is greater in connection with condensate leaks as compared with gas leaks. A narcotic effect can occur very quickly - typically after just 4-5 breaths, if the concentration is high enough.

The narcotic effect of hydrocarbons can cause a person to act irrationally in a hazard situation, and may thus impede the person's ability to escape from the hazard in time. The ability to make rational assessments may be significantly reduced. The difference between concentrations that lead to a narcotic effect and concentrations that lead to loss of life may be very small.

Hydrocarbon releases may also be a relevant factor in relation to long-term health effects. Depending on the type of hydrocarbon, releases may entail high concentrations of compounds such as benzene. Benzene is carcinogenic, however, the mechanisms that lead to development of cancer as a result of benzene effects are largely unknown. Therefore, we cannot rule out that brief exposure to high levels can contribute to an increased risk of cancer.

Contact in the PSA
Sigvart Zachariassen