According to OSHA definitions, VF is an HHC. This incident clearly demonstrated that
VF can enter the slurry tanks; additionally, the tanks are interconnected to the process that uses VF and are physically close to the flash tanks that remove VF. Despite DuPont’s failure to correctly include the slurry tanks in the Tedlar PSM boundary limits, OSHA did not cite DuPont for failing to apply PSM to the slurry tanks.