Has the theoretical risk shown by the mathematical model been confirmed by scientific observation?
Response: The mathematical model used to assess risk is based on scientific observation, i.e., on epidemiological studies of disease in cohorts of exposed workers. It cannot be considered to present “theoretical risk,” since it is a real-world model, constructed from real-world studies of workers who were made ill and died from asbestos exposure. The studies support the use of a linear model. In view of such evidence, OSHA did not have the freedom to postpone action until an epidemiological study became available that confirmed OSHA’s risk assessment through observation of excess deaths of exposed workers. Such an epidemiological study would entail following an extremely large cohort of employees, who are exposed at levels below the PEL, for the lengthy period of time necessary to account for the latency of cancer. It remains OSHA’s responsibility to make practical inferences about occupational health risks on the basis of existing evidence. Question 4. Is it OSHA’s position that any a
