Oleum, which is a mixture of sulfuric acid and sulfur trioxide, is listed as a regulated toxic substance in 40 CFR §68.130.
Sulfur trioxide is also listed individually as a regulated toxic substance.
Suppose a single process consists of one vessel containing oleum and one vessel containing sulfur trioxide. Must the amount of sulfur trioxide in the oleum be aggregated with the amount of pure sulfur trioxide in the process when determining whether the threshold quantity for sulfur trioxide is exceeded?