H2S Overview
The following is a brief overview of Hydrogen Sulfide (H2S) as
it pertains to work safety in the oil and gas industry.
H2S is naturally formed when bacteria break down organic
material in the absence of oxygen. This formation can occur deep
within the earth, such as in volcanoes and in crude petroleum,
or relatively close to the surface in swamps, sewers, wells, and
hot springs. Known by other names such as Hydrogen Sulphide,
Sulfane, Sulphur Hydride, Dihydrogen Monosulfide, Sulfurated
Hydrogen, Sewer Gas and Stink Damp; it is a highly toxic and
colorless flammable gas that has a smell similar to rotten eggs.
It should be noted, however, that using smell as a way of
determining the presence of H2S is not reliable, as the sense of
smell can be quickly eliminated in the presence of the gas.
H2S can seriously injure or kill exposed individuals. The gas is
heavier than air, so it tends to drift to the bottom of poorly
ventilated spaces such as in well holes and underground tanks.
Inhalation of the escaping gas from an open orifice in the
ground usually, but not always, results in death. At lower
levels of concentration, a burning sensation in the eyes, nose,
throat and lungs can be felt, where at higher levels of
concentration a single breath can be fatal. Second man
fatalities can occur when trying to rescue a fallen victim as by
the time it is known that H2S is the cause it is too late for
the rescuer. Training programs and proper equipment must be
provided for all workers who deal with the presence of H2S gas
in their environment even if the gas is remotely expected to be
encountered.