40 CFR 370.42

How do you calculate the average daily amount for EPCRA Tier II?

To get the EPCRA Tier II average daily amount, add up the amount of the chemical on site for each day it was there during the calendar year, divide by the number of those days, and report the range code from 40 CFR 370.43(a). That method comes from EPA's Tier II instructions. The rule itself, 40 CFR 370.42(s)(7), only asks for an estimate in ranges, and no federal text says which amount counts for one day.