A hazard can be defined as the set of inherent properties of a substance that makes it capable of causing harm to humans (Cohrssen and Covello, 1989). The likelihood of harm resulting from exposures determines the risk. As noted in Chapter 5, under certain circumstances (e.g., high exposures or prolonged contact) every nickel species may be capable of causing some type of harm4. It is therefore very important to identify all potentially harmful substances and to monitor and control exposures in order to manage the risk.
With respect to hazards, all the nickel species present in an industrial setting should be identified and a complete inventory made of raw materials used, materials produced, by-products and contaminants (Grosjean, 1994; Verma et al., 1996; ICME, 1999). Consideration should be given to monitoring these materials not only under normal operations, but also when short- term peak exposures occur (e.g., during maintenance). In addition, a record should be made of all procedures and equipment used (including control equipment such as local exhaust ventilation and respirators), changes in processes, and changes in feed materials. Preparing flow charts and floor plans can help to identify areas where potentially harmful substances might exist (Duffus, 1996; Verma et al., 1996; ICME, 1999).
Complementing this description of the physical plant should be a description each of the worker’s employment history. Such a work history should include both past and present employment (Hall, 2001). A past employment history should include:
- All previous workplaces.
- All previous workplace exposures (both qualitative and quantitative).
- Duration of all previous workplace assignments.
- Nature of work performed at all previous worksites.
Present employment records should include:
- Date of start of work assignments at present employment.
- Duration of all work assignments at present employment.
- Nature of work performed with each work assignment.
- Exact location of each work assignment performed.
- Details of exposure (e.g., nickel-containing substances, dusts, noise). Measurements pertaining to the work assignment (particularly noting whether these measurements are based on static or personal sampling and how they were obtained (see Chapter 7 for further discussion).
- Health surveillance/biological monitoring records where appropriate (see Section 6.3 below).
Periodic updates of exposure data and job histories should be conducted on all workers.