To rate the hazard, you need to know what is the consequences of that particular hazard.
By consequence, it means what HARM can the hazard effect your health.
The HAZARD CONSEQUENCES/HARM can be rated as:
1 - Slight Health Effects : Not affecting work performance or causing disability
2 - Minor Health Effects : Hazards capable to cause minor health effects which are REVERSIBLE for instance: Irritant Chemical
3 - Major Health Effects : Hazards capable of causing IRREVERSIBLE health damage without loss of life. Examples: Noise which can cause Hearing loss and impairment
4 - PERMANENT TOTAL DISABILITY or One to 3 Fatalities : Hazards capable of causing IRREVERSIBLE DAMAGE with SERIOUS disability or Death.
Examples : Corrosive chemicals, Psychological Stress, Carcinogens
5 - Multiple FATALITIES : Hazard that has potential to cause multiple fatalities.
Example: Chemicals with Acute Toxic Effects - Carbon Monoxide Poisoning
Generally, Hazard Consequences or Health Effects can be categorised as Acute Health Effect and Chronic health Effect. Knowledge on Industrial Toxicology is essential especially to know the acute and chronic health effects of chemicals.
Referring to Chemical Safety Data Sheet (CSDS) and doing literature review on the health hazards are two important ways to find out the health effects of the hazard in order to RATE THE HAZARD.
After you have done Hazards Rating and enter it in your HHI/HR, now you should find out what is the Risk of getting the consequence of that hazard.
For that, you are at STEP 2 to Risk Assessment. Next posting is on ASSESS THE RISKS.