Comments on 'Implications of hormesis for industrial hygiene'

Although demonstrated evidence for hormesis of an agent could be important in setting occupational exposure limits (OELs) for industrial hygiene, several practical problems may limit the utility of toxicologic testing for hormesis. This commentary responds to the lead article of this section, in which Jayjock and Lewis propose using the results of tests for hormesis to guide the establishment of OELs. The principal difficulties may include: a different mechanism or even a different effect leading to the conclusion of hormesis; distinction between a threshold for a health effect and a crossover point in the dose response relationship; estimation of threshold or crossover point from limited test data and estimation of slope at this point; sensitivity of tests for hormesis; and cost of testing. Nevertheless, the proposals of Jayjock and Lewis have considerable merit, and exploratory testing could be useful.