A facility has a mixture which contains extremely hazardous substances.  The Material Safety Data Sheet (MSDS) for the mixture only indicates a range of concentration for its components.  For the purposes, of reporting under EPCRA Sections 302, 304, and 311/312 of EPCRA, should the facility owner/operator report be based on the lower, upper, or mid-point concentration of each component?

If the MSDS for the mixture indicates only a range of concentration for its components, then for purposes of reporting under Sections 302, 304, and 311/312 of EPCRA, the facility owner/operator should use the upper bound concentration when determining the weight of each component in the mixture.  Such reporting is consistent with the purpose of EPCRA, which is to maximize local communities' opportunities to know about local chemicals and to plan for emergencies.