Toxic Gas Hazards

Gaseous toxic substances are especially dangerous because they are often invisible and/or odourless. Their physical behaviour is not always predictable: ambient temperature, pressure and ventilation patterns significantly influence the behaviour of a gas leak. Hydrogen sulphide for example is particularly hazardous.

Hazardous and Highly Toxic Gases.

Toxic gases (or noxious gases) are gases that are harmful to living things. They can easily build up in confined working spaces when the production process uses noxious gases. It may also result in the biological chemical breakdown of a substance that is being stored in a tank.

The following toxic gases are the ones most commonly encountered in confined space work:

Hydrogen Sulfide – This is also known as sewer gas and has a smell like rotten eggs. However, exposure leads to a loss of smell, so a person might think that the gas is no longer present
Carbon Monoxide – A colorless, odorless gas that is produced when carbon-based fuels, such as wood or coal, are burnt
Solvents – Solvents like kerosene, paint stripper, and degreaser can cause problems with the central nervous system

A toxic gas is one which is capable of causing damage to living tissues, impairment of the central nervous system, severe illness or, in extreme cases, death when it is ingested, inhaled, or absorbed by the skin or eyes.