I like to have some insights as to how mental condition of employee can be gauged while preparing for the risk assessment of a work activity, as suggested in the defintion of ‘ill health.’

Please enlighten, my friend.

The approach to definitions in ISO standards (also used for OHSAS 18001) is that if a word is not defined in the standard, you look to the dictionary definition. There are several possible dictionary definitions of “hazardous”; however, the one that fits best is “creating a hazard.” (Merriam-Webster’s Dictionary of Law cited on http://www.dictionary.com). Hazard is a defined term in the standard. It is defined as “source, situation, or act with a potential for harm in terms of human injury or ill health, or a combination of these”. Therefore, a risk, for purposes of OHSA 18001, is a “chance of harm” that takes into account both the probability (likelihood of occurence) and the severity of potential harm.

An organization determines its “risks” (chances of harm) associated with the hazardous events or hazardous exposures that can arise from its “hazards” in order to identify and implement the controls that will reduce its risks to an acceptable level (defined as “acceptable risk”). The process by which an organization does this determination is called risk assessment.