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

---
identifier: "/us/cfr/t40/s355.13"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 355.13 - How do I calculate the quantity of an extremely hazardous substance present in mixtures?"
title_number: 40
title_name: "Protection of Environment"
section_number: "355.13"
section_name: "How do I calculate the quantity of an extremely hazardous substance present in mixtures?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "J"
subchapter_name: "SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS"
part_number: "355"
part_name: "EMERGENCY PLANNING AND NOTIFICATION"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Sections 302, 303, 304, 325, 327, 328, and 329 of the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA) (42 U.S.C. 11002, 11003, 11004, 11045, 11047, 11048, and 11049)."
regulatory_source: "73 FR 65462, Nov. 3, 2008, unless otherwise noted."
cfr_part: "355"
---


# 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:

EHS (in pounds)

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

= (20 percent) × (150 pound mixture)

= (0.20) × (150)

EHS (in pounds)

= 30 pounds