CONCEPTS OF FITNESS - exposure risk (adverse impacts of exposure on fitness) and capability risk (when inherent requirements of the job cannot be met)

The Occupational Health and Safety Act requires people in occupations that entail potential exposure to certain hazards (such as noise, lead, hazardous chemical substances and hazardous biological agents) to be subjected to medical screening, to determine their fitness to work in the said occupations.

In the mining industry, all employees involved in "risk work" are required to undergo an initial medical examination and be certified fit for work by an Occupational Medicine Practitioner prior to their engagement in risk work. This needs to be repeated at a prescribed periodicity. This process is legally prescribed in both the Occupational Diseases in Mines and Works Act (ODMWA) and in the Mines Health and Safety Act. Historically, this certificate is known as "The Red Ticket", a term which is derived from the document which was issued to employees by the Medical Bureau of Occupational Diseases, authorising them to perform risk work. This was a red coloured card, which certified fitness to work for a prescribed period of time. At the end of the authorised period, the employee was required to undergo a periodic medical examination, to ensure that he/she continued to meet the minimum standards of fitness to perform risk work.

The concept of fitness can therefore be seen to be closely associated with the concept of "risk". Risks fall into two broad categories:

1. Exposure risks (Risks flowing from the environment and agent):

This refers to risks associated with exposure to hazards in that occupation. These hazards include noise, heat, dust, ergonomic hazards, etc., and have potential or actual adverse health effects for exposed workers which may reduce their capability to perfom the tasks in their given occupation without further endangering their health.

2. Capability risk (Risk flowing from factors inherent to the host which are necessary to perform the occupational tasks safely):

Certain occupations require of the employee the capability to conduct the tasks that comprise the occupation in a manner that does not increase the likelihood of injury or illness to either themselves or to co-workers. Failure to meet these requirements raises employer liability for claims from both outside and inside the company consequent on accidents caused by employees who lack the capacity to do the job properly. An example of increased risk of litigation from outside the company could arise from a truck driver with inadequately controlled epilepsy, while increased risk from inside could arise from employing a person to work with a dangerous power tool who has no training in how to operate it.

Therefore the concept of "fitness to work" implies that an occupation has both exposure risks for hazards associated with the occupation, and also inherent health requirements that need to be met by a person in that occupation.

This dual view of fitness and risk allows graphical representation of fitness requirements in a two by two table in Figure 1.

Figure 1: The relationship between capability risk and exposure risk.

		EXPOSURE RISK +	EXPOSURE RISK -
	CAPABILITY RISK +	critical occupations (example: crane driver)	capability occupations (example: bulk truck driver)
	CAPABILITY RISK -	hazardous occupations(example: welding)	general occupations(example: office work)

This illustrates the two basic axes of risk - the vertical axis represents increasing inherent health requirements of the job (capability risk), and the horizontal axis represents increasing potential exposure to hazards (exposure risk). This leads to four main "risk-groups" of occupations:

• Those with high health requirements, but low hazard exposure - the "capability occupations". (such as bulk truck drivers, heavy passenger vehicle drivers).
• Those with high health requirements, and high hazard exposure - the "critical occupations". (such as crane operators, forklift drivers, certain machine operators).
• Those with low health requirements, but high hazard exposure - the "hazardous occupations". (such as welding, maintenance, or any work entailing exposure to significant hazards).
• Those with low health requirements, and low hazard exposure - the "general occupations". (such as general workers, office and administration staff, etc.).

This model shows the dual requirement of the Medical Screening Programme to evaluate employees for both of these axes of risk. The programme should ensure that minimum medical requirements are met by employees, and also that any adverse health effects from the exposure to hazards in the workplace are detected at an early stage, enabling effective remedial action to be taken

REFERENCES:

1. Occupational Health and Safety Act (OHSA), No 85 of 1993 and Regulations.
2. The Mines Health and Safety Act (MHSA), No. 29 of 1996 and Codes of Practice.