What are the effects of H2S exposure?
H2S is a very toxic gas. The UK Health and Safety Executive states that the maximum peak exposure is 15 minutes at a 10 ppm concentration. Their acceptable concentration limit for H2S is 5 ppm for an eight-hour period.
H2S has no colour but can be detected by the smell of rotten eggs, however in larger amounts, H2S can quickly block the sense of smell. The gas can irritate the eyes, nose, throat, and lungs. Too much H2S can be fatal. H2S dissolves in water and oil, and it may be released when these liquids are heated or agitated.
Because H2S is heavier than air, it may settle in low spots. This can pose risks when entering areas where the gas may be present. H2S burns and explodes easily. When it burns, H2S gives off sulphur dioxide, another dangerous gas that is toxic, strong smelling, and irritating.
Hydrogen sulfide is one of the most serious corrosion agents encountered in the oil and gas industry. In addition to its ability to crack metals, it can also result in pitting corrosion with subsequent failures. The release of H2S as a result of corrosion or cracking can endanger the lives of people working around, or in near proximity to, the release point. Therefore, designing equipment resistant to H2S cracking is critical.
In labelling solutions, exposure to H2S can cause discolouration, loss in mechanical performance, shrinkage and loss of adhesion. Silver Fox labels have been tested in environments equivalent to 50 years of service.