Determining the Population at Risk

A worker is “at risk” if he or she has a greater chance of developing disease than a similar, but non-exposed worker (Verma et al., 1996). Using this broad based definition of an “at risk” worker, it is clear that not only production workers, but office workers and support staff may have occasion to be exposed to nickel and its compounds in various industrial settings. Consideration should also be given to contractors, such as temporary workers or long-term maintenance crews employed at factories, as some of these workers may be employed in potentially high exposure jobs. While the management and follow-up of contractors may not be the direct responsibility of a given nickel company, it may, nevertheless, be useful in some nickel operations to document contractors’ exposures and maintain records. Hence, for purposes of risk assessment, records should be kept on most, if not all, workers employed in the nickel industry. Companies should assign a unique identifier to each individual. Use of last names and/or birth dates is not recommended, as such identifiers may be shared by more than one employee. Sequentially assigning numbers to workers at date of hire or devising alpha/numerical codes for each individual is preferred. Once assigned to a worker, a number should always refer to that individual only.

Identification information that should be recorded includes the employees’ full name and that of his or her parents, birth date, gender, place of birth, ethnic origin, other significant dates (such as date of hire, date of departure, date of death, etc.) and other potentially identifying data (such as social security or medical insurance numbers). Records should be periodically updated (even after employees have retired or left for other employment); they should also be well maintained and easily retrievable (Verma et al., 1996). Consideration should be given to creating coding that would be universal throughout the nickel industry so that meaningful epidemiological studies can be optimized (Hall, 2001). This would apply not only to identification data, but to any data collected as part of a health surveillance program (see below).

(3) The International Council on Metals and the Environment, now known as the International Council on Mining and Metals.