You are asked to evaluate a set of exposure data for a setting where workers are exposed to a mixture of two chemicals with different toxicological endpoints. How do you determine if the observed exposures are within acceptable limits?

a. Consider each chemical separately, then add the ratio of concentration/exposure limit for each.

b. Exposures of this type are synergistic, so the PELs are multiplied

c. OSHA does not address this scenario, therefore you must refer to ACGIH guidance

d. Consider each chemical separately