40 CFR 370.10 · 40 CFR 355 App. A

EPCRA Tier II threshold checker

Know which tanks put the site on the Tier II list.

List each chemical with its largest amount on site. The tool converts gallons to pounds by SG, totals each chemical across rows, and compares it with the 40 CFR 370.10 threshold, using the EHS list in 40 CFR 355 Appendix A.

Last updated 2026-09-28. Math runs in your browser, no data leaves your computer.

Add one row per product, tank or storage area. Enter the largest amount present at any one time during the year, not the amount bought, because that is the figure 40 CFR 370.10 tests.

Two rows with the same CAS number are added together, since a chemical has to be counted across the whole facility, pure and in mixtures alike. A chemical with no match on the EHS list is tested at 10,000 lb, on the basis that OSHA requires an SDS for it.

Before the booking, screen the name on the invoice. Shipment pre-check is on the paid plans, from USD 59 a month.

General guidance only. Verify against the cited primary sources before you commit to a shipment, declaration, or contract.

How the thresholds are applied

Each row is converted to pounds, using 3.785411784 liters per US gallon and 0.45359237 kg per pound, and multiplied by the weight percent. A component at or below 1 percent is dropped, as 40 CFR 370.14(c) allows. Rows that resolve to the same CAS number are added together.

The CAS number is then looked up in the 355 extremely hazardous substances in 40 CFR 355 Appendix A, read from eCFR on 24 September 2026. For a listed substance the threshold is the lower of 500 lb and its TPQ, and for anything else it is 10,000 lb. The 0.2 and 0.3 reduction factors in 355.16 are not used, because the regulation says they do not apply to the 370.10 count.

The tool does not decide whether OSHA requires an SDS for a product, and it does not know which components are carcinogens. It also does not apply the retail gas station thresholds for gasoline and diesel, so read 370.10 directly if those apply to you.

Worked example. A warehouse that planned on 10,000 lb

The booking. A chemical distributor's warehouse holds two 275 gallon totes of 93 percent sulfuric acid, SG 1.83 from the SDS, alongside 30,000 lb of sodium hydroxide beads. The EHS manager plans the Tier II filing on the 10,000 lb rule, reports the caustic, and counts the acid at 2 × 275 × 1.83 × 8.3454 × 0.93 = 7,812 lb, which is under 10,000 lb and looks fine on paper.

The failure. Sulfuric acid is an extremely hazardous substance with a TPQ of 1,000 lb, so its Tier II threshold is 500 lb, not 10,000 lb. The site holds more than fifteen times that, and a missed chemical on the March 1 inventory is a reporting violation. The choice is straightforward: add the acid to the report, or cut the stock below 500 lb.

The fix. The manager enters both products here. The caustic shows as reportable at 30,000 lb against 10,000 lb, and the acid shows as reportable at 7,812 lb against 500 lb, so both go on the inventory, and the acid also goes into the emergency planning notice under 40 CFR 355, since the site holds more than its 1,000 lb TPQ.

The same acid carries a 1,000 lb reportable quantity for spills and shipments. The RQ lookup checks whether each tote needs RQ on the shipping paper.

Frequently asked

What are the Tier II reporting thresholds?

Under 40 CFR 370.10, a facility reports a hazardous chemical present at any one time at 10,000 lb or more. An extremely hazardous substance is reported at 500 lb or its threshold planning quantity, whichever is lower. Gasoline and diesel at a retail gas station have their own thresholds of 75,000 and 100,000 gallons when held in compliant underground tanks.

What is the Tier II threshold for sulfuric acid?

Sulfuric acid is on the extremely hazardous substance list in 40 CFR 355 Appendix A with a TPQ of 1,000 lb. The Tier II threshold is the lower of 500 lb and the TPQ, so it is 500 lb of sulfuric acid, counted across every drum, tote and tank on the site.

How do I count a chemical inside a mixture?

Multiply the weight percent of the chemical by the weight of the mixture, as 40 CFR 370.14(c) sets out, and add that to every other quantity of the same chemical on the site. You do not have to count a component at or below 1 percent, or at or below 0.1 percent for a carcinogen. The tool applies the 1 percent cut, so flag any carcinogen yourself.

Which TPQ applies to a solid EHS with two values, such as 500/10,000?

The lower value applies when the solid is a powder under 100 microns, in solution, molten, or rated 2, 3 or 4 for reactivity by NFPA, per 40 CFR 355.15. Otherwise the TPQ is 10,000 lb. For Tier II the threshold is still capped at 500 lb, so the form only changes the answer when the lower TPQ is under 500 lb.

When is the Tier II report due, and where do I file it?

The inventory is due on or before March 1 each year and covers the chemicals present during the previous calendar year, under 40 CFR 370.45. It goes to the state emergency response commission, the local emergency planning committee and the fire department. Each state runs its own filing system and some set their own rules, and EPA's state page links to every one.

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Sourzi shows what official files say. It is not customs or legal advice. For a binding answer, ask a licensed customs broker, a CBP ruling or an Australian Border Force Tariff Advice.

File dates and links are on Data sources.