Classification of hazardous substances and their associated health risks

Classification of hazardous substances and their associated health risks 

Irritant is a non-corrosive substance which can cause skin (dermatitic) or lung (bronchial) inflammation after repeated contact. People who react in this way to a particular substance are sensitized or allergic to that substance. In most cases, it is likely that the concentration of the irritant may be more significant than the exposure time. Many household substances, such as wood preservatives, bleaches and glues are irritants. Many chemicals used as solvents are also irritants (white spirit, toluene and acetone). Formaldehyde and ozone are other examples of irritants. 

A corrosive substance is one which will attack, normally by burning, living tissue. It is usually a strong acid or alkali and examples include sulphuric acid and 

Harmful is the most commonly used classification and describes a substance which, if it is swallowed, inhaled or penetrates the skin, may pose limited health risks. These risks can usually be minimized or removed by following the instruction provided with the substance (e.g. by using personal protective equipment). Many household substances fall into this category including bitumen-based paints and paint brush restorers. Many chemical cleansers, such as trichloroethylene, are categorized as harmful. It is very common for substances labelled harmful also to be categorized as irritant. 

Toxic substances are ones which impede or prevent the function of one or more organs within the body, such as the kidneys, liver and heart. A toxic substance is, therefore, a poisonous one. Lead, mercury, pesticides and the gas carbon monoxide are toxic substances. Carcinogenic substances are ones which are known or suspected of promoting abnormal development of body cells to become cancers. Asbestos, hard wood dust, creosote and some mineral oils are carcinogenic. It is very important that the health and safety rules accompanying the substance are strictly followed. 

---