40 CFR 355.13 - How do I calculate the quantity of an extremely hazardous substance present in mixtures?

U.S. Code of Federal Regulations

Regulations most recently checked for updates: Aug 28, 2025

View all text of Subpart B [§ 355.10 - § 355.21]

§ 355.13 - How do I calculate the quantity of an extremely hazardous substance present in mixtures?

If an EHS is present in a mixture in a particular container, determine the quantity (in pounds) of the EHS in that container by multiplying the concentration of the EHS (in weight percent) by the weight (in pounds) of the mixture in the container. If the concentration of an EHS is less than or equal to one percent in the mixture, you do not have to count that EHS. Here is an example calculation:

Example:You have 150 pounds of a mixture that contains 20 weight percent of a certain EHS. The quantity of EHS present in the mixture is: EHS (in pounds)

= (weight percent of EHS) × (weight of mixture)

= (20 percent) × (150 pound mixture)

= (0.20) × (150) EHS (in pounds) = 30 pounds