In terms of Regulation no. 5 of the Hazardous Chemicals Regulations of the OH&S Act, an assessment must be made on all hazardous chemicals used or being manufactured in an operation. This must be repeated at least once every two years. This assessment must point out the route of entry into the body, the affect the chemical may have on the various organs, its target organs and a risk rating.
Substances that are regarded as hazardous (listed in one of the tables of the Hazardous Chemicals Regulations) include Sucrose, hydrogen peroxide (bleaching of hair?), manmade fibres (e.g. polyester), Plaster of Paris, Turpentine etc. to name a few household names. The Regulation has three tables: Table one has exposure levels that may not be exceeded and requires annual air monitoring, Table two has exposure levels that should not be exceeded and requires air monitoring once every two years and table 3 requires biological monitoring. A substance may be in more than one table. Also chemicals that are not listed but do pose a risk to the body needs to be evaluated.
There are different ways of working out risks. We use the American Safety Associations method of risk rating. In a nutshell it states that the risk is:
Risk = exposure concentration x exposure frequency x toxicity
These are all weighting, i.e. approximations. Once the risks for each substance has been worked out, one can formulate a strategy to reduce some of the higher risks substances by substituting a higher toxic substance with a lower toxic substance (e.g. Methanol vs. Ethanol) or reducing the exposure by going from drummed material to semi bulk or bulk.
The results from the Risk Assessment are used to work out a strategy for air monitoring – should it be done and if so, what substances need to be tested for. This is a requirement under Reg. 6 of the Hazardous Chemical Regulations.
The information contained in a good Risk Assessment could also be used in a training program to educate the workers on the dangers each chemical poses (also a legal requirement under Reg. 3 of the said Regulations). If one is aware of the dangers these chemicals pose, one can work accordingly: workers who are not informed may think that every chemical is like water.
A risk assessment is not there to tell people that they should not work with a chemical, it only highlights the dangers these chemicals pose. I have worked with Sodium Cyanide (highly poisonous) yet I am still healthy because I was aware of its dangers.