Hydrogen Sulfide and Why It Kills at Work

Hydrogen sulfide is a gas made of hydrogen and sulfur. Its chemical formula is H2S, and most people at work simply call it "H2S". In British spelling it is written "hydrogen sulphide". It is the same gas.

Hydrogen sulfide has no colour. At very low concentration it smells of rotten eggs. At higher concentration it stops a person smelling anything at all, and at high concentration one or two breaths can make a person collapse. A person who collapses in the gas and is not removed quickly will die.

This is why hydrogen sulfide is treated differently from most other workplace gases. With many hazards a mistake gives a warning first. With hydrogen sulfide at high concentration, the first sign can be a worker lying on the ground.

Knowledge here, practice in person

Breathing apparatus cannot be learned from a screen. A person has to put the set on, feel the mask seal on the face, breathe from it and move in it, with a competent instructor watching. That hands-on practice is done in person, for example in the classroom course H2S (Hydrogen Sulfide) Safety, which includes a practical session on breathing apparatus, or in the training your employer or site requires.

Your site also has its own rules: its own alarm levels, its own muster points and its own contingency plan. Where this course gives a number, it names whose number it is. Where sites differ, the course says so, and your site procedure decides.