Protecting oil and gas workers from H2S

Hydrogen sulphide (H2S) causes challenges for many industries, with the oil, gas and petrochemicals industry being one of the most affected, says MSA Safety

Hydrogen sulfide is a highly flammable, toxic and corrosive gas found in several industries including oil and gas, wastewater and chemical processing, which cannot reliably be detected by smell.

Oil, gas and petrochemical facilities handle raw ‘sour’ gas and oil which are naturally high in H2S. Extraction and refining processes release H2S, which may accumulate in confined, poorly ventilated spaces like processing units, pipelines and storage tanks. Closed systems with high-pressure conditions amplify the risks for workers.

Exposure to high levels of H2S can be fatal, leading to loss of breathing, coma, seizures and death. It is the second most common cause of fatal gas inhalation exposure in the workplace, second only to carbon monoxide.

H2S can also be harmful at low concentration levels, causing headaches, dizziness, nausea, breathing difficulties and a sore throat. These health impacts can become more serious with prolonged exposure.

The health impacts of H2S depend on how much is inhaled and for how long. The recommended exposure limit set by NIOSH (the US National Institute for Occupational Safety and Health) for ten minutes is 10 ppm.

However, some U.S. states have developed ambient air standards for H2S well below OSHA and NIOSH standards due to concerns about health risks from chronic exposure.

For longer exposures to H2S, the recommended limits are much lower. For example, if you are exposed for up to 24 hours, the World Health Organisation (WHO) recommends a maximum exposure of 0.1 ppm.

In response to concerns about the risks of H2S to human health even at low concentration levels, some countries have introduced equally stringent guidelines requiring businesses to monitor H2S at such concentrations.

Balancing safety and operational efficiency is an ongoing challenge in the oil, gas and petrochemical industry. Some are tackling this challenge by integrating new technological solutions into their safety management practices and seeking out effective preventative measures, including regular training and effective ventilation. The use of Personal Protective Equipment is also important.

A particularly helpful method for avoiding excessive H2S exposure is constant monitoring by advanced gas detection systems such as MSA’s ALTAIR io 4 Connected Gas Detector, which can give an early warning of even subtle increases in H2S concentration, helping companies stay ahead of potential risks. The company has recently updated this to offer the option of a low-concentration hydrogen sulfide sensor that can detect H2S at very low levels.

Connected gas detection devices can help an organisation significantly improve worker safety by providing real-time monitoring of gas levels and worker location and behaviour, enabling safety managers to monitor the situation remotely and take immediate action if gas levels become or get close to becoming dangerous. This proactive approach to safety can help prevent accidents and foster a culture of safety within the organisation.

As with all toxic gases, early detection of H2S is an excellent way to alert safety managers to small increases in H2S emissions so they can help workers avoid harmful exposure, even at low concentrations.