How do you convert gallons to pounds for Tier II?

To convert gallons to pounds for Tier II, multiply the gallons on hand by the product's density in pounds per gallon. The EPA's May 2026 Tier II instructions write it as pounds = density (lbs/gal) × gallons on-site, with density = specific gravity × 8.34 lbs/gal, and the regulation gives the subject one sentence, Note 1 to 40 CFR 370.43(a). The weight then goes on the form as a range code in pounds, 01 through 13, unless your SERC or LEPC sets its own codes or asks for specific amounts.

Fuel tickets record the jobsite’s diesel tank in gallons. Form release comes in 55-gallon drums, curing compound in 5-gallon pails, and solvent in quart cans. Before comparing these quantities with a Tier II threshold expressed in pounds, convert the volume using the density of the product. The special retail-gas-station thresholds are described below.

Tier II is an EPA form, filed under section 312 of EPCRA (42 U.S.C. 11022) and 40 CFR Part 370. The federal text on the conversion is that one note, with no density value in it and no fallback for an SDS that lists none. EPA guidance adds a formula with a worked benzene example. A separate EPA FAQ lets you estimate a liquid at the density of water when its SDS has no density, for threshold determinations. Whether your site has to file at all is covered in EPCRA Tier II chemical reporting for construction.

What are the steps from gallons to a range code?

The table puts the sequence in order, with the text each step comes from. Rows marked guidance come from EPA instructions, which explain the rule without being part of it.

When the SDS of a liquid lists no density, an EPA FAQ allows an estimate at the density of water, 8.3 pounds per gallon, for the threshold determination. Its limits are set out further down.

Is Tier II reported in pounds or in range codes?

In range codes, and each code is a band of pounds. The thresholds come first. 40 CFR 370.10(a)(2)(i) sets the level for most hazardous chemicals:

For any hazardous chemical that does not meet the criteria in paragraph (a)(2)(ii) or (iii) of this section, the threshold level is 10,000 pounds (or 4,540 kg). (40 CFR 370.10(a)(2)(i))

For an extremely hazardous substance (EHS), 370.10(a)(1) uses "500 pounds (227 kg—approximately 55 gallons) or the Threshold Planning Quantity (TPQ), whichever is lower." The TPQ column in 40 CFR Part 355, Appendix A, is headed "Threshold planning quantity (pounds)." The 55 gallons in that parenthesis is a rough equivalence. Divided out, it comes to about 9.09 pounds per gallon, a figure that tells you nothing about what your own product weighs.

Paragraphs (a)(2)(ii) and (iii) hold the only thresholds written in gallons: 75,000 gallons of gasoline and 100,000 gallons of diesel, at retail gas stations, in tanks entirely underground that comply with 40 CFR Part 280 or 281. A fuel tank on a contractor's yard is compared in pounds.

Then the form. 40 CFR 370.42(s)(6) covers the maximum amount:

Provide an estimate (in ranges) of the maximum amount of the hazardous chemical present at your facility on any single day during the preceding calendar year. … You must use the codes that correspond to different ranges. The amounts and associated range codes are in § 370.43. (40 CFR 370.42(s)(6))

Paragraph (s)(7) of 40 CFR 370.42 asks for the same estimate in ranges for the average daily amount. The codes sit in 40 CFR 370.43(a), in a table whose columns read "Weight range in pounds":

The statute asks for the same thing. 42 U.S.C. 11022(d)(2)(B) and (C) call for "An estimate (in ranges)" of the maximum and average daily amounts, and they name no unit. Pounds come from the code table. An EPA FAQ updated March 24, 2026 puts it this way: "EPA only requires the owner or operator to enter ranges for both the maximum amount and average daily amount of the hazardous chemical on Tier II inventory forms."

You still need a weight to pick a code. For the average daily amount, the May 2026 instructions tell you to "total all daily weights and divide by the number of days the hazardous chemical was present on site." A tank log kept in gallons gets converted before it's added up.

Under "Converting liquid gallons to pounds," those same instructions say "All quantities must be reported as weight in pounds." That "must" belongs to guidance. In the regulation, pounds come from the headings of the code table in 370.43(a).

What does 40 CFR 370.43 say about density?

One sentence, set under the code table:

To convert gas or liquid volume to weight in pounds, multiply by an appropriate density factor. (40 CFR 370.43(a), Note 1)

Note 1 to 40 CFR 370.43(a) gives the conversion method without a density value or fallback. Its wording remained unchanged in the 2026 update to the Tier II reporting rules. Use a density appropriate to the product and the units in the inventory.

The note covers a gas or a liquid measured by volume, and the step it describes is a multiplication by "an appropriate density factor." It gives no number. It doesn't say where the density comes from, at what temperature it's measured or in what unit it's written. The formula comes from EPA guidance.

How do you convert gallons to pounds with the EPA formula?

The EPA's Tier II instructions dated May 2026 give it on page 4, under "Converting liquid gallons to pounds":

Pounds = density (lbs/gal) x gallons on-site

Density = specific gravity x 8.34 (lbs/gal)

(EPA Tier II instructions, May 2026, p. 4)

The worked example on the same page starts with one shipment of a solvent mixture that filled five 5,000-gallon storage tanks, and a solvent that contains 10% benzene. "You calculate that 10% of 25,000 gallons is 2,500 gallons. You know that the density of benzene is 7.29 pounds per gallon, so you multiply 2,500 gallons by 7.29 pounds per gallon to get a weight of 18,225 pounds." On the table in 40 CFR 370.43(a), 18,225 pounds is range code 06.

Which instructions apply depends on the report. The EPA's Tier II Forms and Instructions page, updated June 22, 2026, assigns the May 2026 instructions to the report due March 1, 2028, and the June 2017 instructions (v.17) to the reports up to the one due March 1, 2027. The 2017 version carries the same note and the same benzene example at 7.29 pounds per gallon. It does not print the two formulas. Its page 9 reads: "Report all amounts as weight in pounds. To convert gas or liquid volume to weight in pounds, multiply by an appropriate density factor."

Section 9 of an SDS gives a relative density of 1.20, and the jobsite holds 1,000 gallons of the product. By the EPA formula, 1.20 × 8.34 = 10.008 pounds per gallon, so the 1,000 gallons weigh 10,008 pounds. That's just over the 10,000-pound threshold of 40 CFR 370.10(a)(2)(i), and into range code 06.

An inventory kept in liters takes one more step. A density in kilograms per liter, the same number as grams per milliliter, converts at 2.20462 pounds per kilogram and about 3.785 liters per US gallon, which puts 1 kg/L at about 8.345 lb/gal.

The instructions also say "You may also use the EPA Gallon to Pound Conversion Tool." It's a spreadsheet with tabs of densities for fuels, refrigerants, paints, metalworking fluids and a list of chemicals. Its densities come from third-party sources named in the file, among them websites, SDSs and the medians of ranges, and its built-in example talks about gallons "detected in a waste stream." The EPA's FAQ on missing weights sends you to the SDS first: "The density (mass per unit volume) should be noted on the MSDS."

Where is the density on an SDS?

In section 9, "Physical and chemical properties." OSHA's Hazard Communication standard lists what sections 1 to 11 and 16 of an SDS must contain in Appendix D of 29 CFR 1910.1200, which is marked Mandatory. Table D.1 lists, for section 9, item (p): "Density and/or relative density." Item (q), on the next line, is "Relative vapor density." Don't take one for the other.

The appendix sets no unit and no temperature for item (p). Section 9 can give a relative density, which is a ratio with no unit, or a density with a unit attached. The EPA formula multiplies a specific gravity, which is a relative density, by 8.34. A density already in pounds per gallon goes straight into the first formula, and one in kg/L goes through the conversion above.

For a missing value, the appendix says what the SDS has to do: "If no relevant information is found for any given subheading within a section, the SDS shall clearly indicate that no applicable information is available." Appendix D sits in the general industry standard and is addressed to whoever prepares the SDS, the manufacturer, importer or distributor. For the Tier II filer, it tells you where the density should be printed. The EPA FAQ still says MSDS, and the note to 40 CFR 370.10(a) settles the vocabulary: "The terms MSDS and SDS are synonymous." For a walk through the other sections of the sheet, see how to read a safety data sheet.

What if the SDS doesn't list a density?

The sections that set the thresholds and the form don't say. None of sections 370.10, 370.14, 370.42 or 370.43 of 40 CFR tells you where to get a density or what to do without one, and none sets a default value.

The EPA answered the question in an FAQ, "Threshold determinations when there is no weight indicated on MSDS," updated April 14, 2026:

If a liquid is not labeled in pounds, its weight can be calculated by multiplying the liquid's volume by its density. The density (mass per unit volume) should be noted on the MSDS. If the liquid's density is not indicated on the MSDS, the facility owner or operator may estimate the weight based on the density of water (8.3 pounds per gallon, or 2.2 pounds per liter), when making EPCRA §312 threshold determinations. (EPA FAQ, updated April 14, 2026)

The wording sets the limits. The FAQ speaks of a liquid, says "may," and applies to threshold determinations, in answer to a question about "threshold and applicability determinations." It doesn't say the water figure carries over to the range code you report once a product is over the threshold, and it says nothing about a gas or a solid.

The EPA writes water three ways: 8.3 pounds per gallon in this FAQ, 8.34 in the specific-gravity formula of the instructions, and 8.33 in the Gallon to Pound Conversion Tool, which says "The density of metalworking fluids is assumed to be equivalent to the density of water, or 8.33 lbs/gallon." They're three roundings of the same quantity.

The estimate can move a product across the line. Go back to the 1,000 gallons at a relative density of 1.20. Had the SDS listed no density, the water estimate would have put them at 8,300 pounds, under the 10,000 pounds of 40 CFR 370.10(a)(2)(i). With the density, they weigh 10,008 pounds and the product is over. A liquid lighter than water comes out heavier under the estimate than it is.

A blank item (p) is worth a written question to the supplier, and the reply belongs in the Tier II file.

How do you count a chemical inside a mixture?

40 CFR 370.14(c) sets the arithmetic:

To determine the quantity of an EHS or a non-EHS hazardous chemical component present in a mixture, multiply the concentration of the hazardous chemical component (in weight percent) by the weight of the mixture (in pounds). You do not have to count a hazardous chemical present in a mixture if the concentration is less than or equal to 1%, or less than or equal to 0.1% for a carcinogenic chemical. (40 CFR 370.14(c))

The rule starts from the weight of the mixture. A mixture bought by the gallon goes through the density step first, with the density from the mixture's own SDS, and the weight percent of 40 CFR 370.14(c) then applies to that weight. Table 1 in 40 CFR 370.14(a) also lets you "Report the mixture itself," and "If you report the mixture itself, then provide the total quantity of that mixture." The May 2026 instructions give a chlorine example on page 5: "If a solution of chlorine weighs 100 pounds and is composed of 5% chlorine and 95% water, you may report either 5 pounds of chlorine or 100 pounds of the mixture."

When the composition is unknown, the EPA's mixtures FAQ, updated April 14, 2026, says "facilities should report on the mixture as a whole, using the total quantity of the mixture." When an EHS is in the mixture, 40 CFR 370.42(s)(6) adds: "If the mixture contains any EHSs, provide the total amount of each EHS in that mixture."

The texts leave two gaps here. The benzene example takes 10% of the gallons, while 370.14(c) is written in weight percent times pounds, and a percentage by volume cannot be substituted directly for the weight percent in 370.14(c). Section 370.14(c) supplies no fallback density for a mixture, and the water FAQ is written for "a particular liquid hazardous chemical."

What does the rule leave open?

The table separates the conversion rule from cases for which it supplies no factor or method. Ask the supplier for missing physical-property data and check your state’s reporting instructions.

If a guide hands you a factor for propane, or a standard temperature, as an EPA rule, ask for the citation. Keep the density you used for each product, and where it came from, on the same line as the gallons.

Can a state require exact amounts?

Yes. 40 CFR 370.43(b) leaves room for it:

Your SERC or LEPC may provide other range codes for reporting maximum amount and average daily amount or may require reporting of specific amounts. You may use your SERC's or LEPC's range codes (or specific amounts) provided the ranges are not broader than the ranges in paragraph (a) of this section. (40 CFR 370.43(b))

The introductory text of 40 CFR 370.42 says "Some states may require you to use a state reporting format including electronic reporting and certification for submitting your hazardous chemical inventory. Contact your state for its specific requirements." The June 2017 instructions say it outright on page 10: "Your state may require you to report exact amount for maximum amount and average daily amount rather than in ranges. Check with your state for specific requirements." The EPA's range-code FAQ of March 24, 2026 also points to 370.43(b) for specific amounts.

Check the state’s instructions for its required amounts, units and reporting format. Where an exact weight is required, retain the density and its source with the calculation. EPCRA Tier II reporting for construction covers filing and deadlines.

How do you complete the densities for a whole jobsite?

On paper, it's two more columns on the inventory sheet, one for the density and one for where it came from, filled in one SDS at a time.

HazComFast does the conversion on the EPCRA Tier II page with the density saved for each product, and it marks every guess as a guess. A product with no density yet shows its weight as "ESTIMATED," and a "Needs Density" card counts how many are waiting. When an estimate reaches 80% of its 40 CFR 370.10(a) threshold, the calculator shows the percentage and asks for the confirmed density before the status counts.

The whole jobsite gets done in one sitting. The "Complete densities" screen lists every product that still needs a density, one row each, in kg/L, lb/gal or kg/m³. "Retrieve all from SDS" reads section 9 of each product's SDS in turn and sets the value it finds beside the row, after "SDS:". You look them over, click "Use all SDS values," and save the batch. If something looks off, "Undo" puts the previous values back.

For a single product, the "Add density" dialog shows the weight the new value gives before you save it, and it catches a typo on the spot. Type 99999 and it answers "Not a plausible density: enter a value between 0.1 and 25 kg/L (SDS section 9)." Typical values for water, solvents, acids, bases, diesel and gasoline sit right underneath, to check against the SDS, and the one behind the current estimate is tagged.

Every saved density keeps its origin: "entered by hand," "confirmed from the SDS" or "typical value, confirmed." When someone asks where a number on your Tier II came from, the answer is on the product.

Related reading: EPCRA Tier II reporting for construction: do you need to file? · Chemical inventory for OSHA and Tier II · How to read a safety data sheet