A suitable study to evaluate colour vision requirements for firefighters?

A recent paper by Rees (Occup. Med. 1994; 44: 253-256) has proposed a study to evaluate the performance of both clinical and trade tests on firefighter recruits. The paper suggests that a new trade test using painted gas cylinders and/or the BOC cylinder identification chart may be appropriate in the selection of firefighter recruits. Evaluation of pass/fail standards on these tests would be achieved by comparing the results with those obtained from the Ishihara test, the City University test and the Holmes-Wright lantern test. In this paper, we argue that the proposed battery of tests does not allow an accurate evaluation of the new trade tests. Indeed,the new trade tests are likely to result in a false sense of obvious fairness' that ultimately be an unsound means of assessing the colour vision requirements of firefighter recruits.