29 CFR 1910.1000 · SWA WES and WEL

OSHA PEL and Australian exposure limit lookup

Know the air limit before the plant starts handling the drums.

Search a name or CAS number to see the OSHA PEL from Tables Z-1, Z-2 and Z-3 next to the Safe Work Australia WES and WEL values, then convert ppm and mg/m3 with the molar mass.

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

Type the name from Section 1 of the SDS or the CAS number from Section 3. The tool reads its own copy of the 29 CFR 1910.1000 tables and both Safe Work Australia lists, so nothing you type leaves the browser.

A CAS number is the quickest match, but OSHA enforces the substance name, so try the name too when a CAS search misses.

Convert ppm and mg/m3

Limits for gases and vapours come in both units, and an air monitor often reads in the other one. Enter the molar mass from SDS Section 9 and one value, and the tool works out the other.

Take it from SDS Section 9 or the supplier COA, because the conversion is only as good as this number.

Pick the basis of the limit you are checking, since the two lists state their conditions slightly differently.

Type a ppm value to get mg/m3, or leave it blank and fill the next box instead.

Type a mg/m3 value to get ppm, and the tool fills whichever box you left empty.

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.

Where the numbers come from

The OSHA rows are copied from Tables Z-1, Z-2 and Z-3 of 29 CFR 1910.1000 as eCFR published them on 24 September 2026. A Z-1 value marked (C) is a ceiling, every other Z-1 value is an 8 hour time weighted average, and a row that says "see 1910.10xx" means the substance has its own standard with its own limits and rules.

The Australian rows come from the two Safe Work Australia documents amended in November 2025. The WES list applies until 30 November 2026, and the WEL list applies from 1 December 2026, so a site that is being designed now should be designed to the WEL figure.

The tool matches rows by CAS number first and by exact name second, and only when a list has no exact name does it show entries whose name starts with the words you typed. It never guesses a match between two names that merely look alike, so a miss means the tool found no row, not that the substance has no limit.

Worked example. A toluene line moving to an Australian plant

The booking. A US coatings maker is copying its toluene wash line to a new plant in Victoria and sends over its ventilation design. The design holds the air at half the OSHA figure, and Table Z-2 gives toluene an 8 hour TWA of 200 ppm with a 300 ppm ceiling, so a 100 ppm design target looks fine on paper.

The failure. The Safe Work Australia WES puts toluene at 50 ppm TWA, and the WEL list that starts on 1 December 2026 cuts it to 20 ppm with an ototoxic notation. A 100 ppm design is twice the WES figure today and five times the WEL figure that applies from December. The choice is the usual one: redesign the extraction, or change the solvent.

The fix. The engineer resizes the extraction to hold 10 ppm, half the WEL. With the molar mass of 92.14 g/mol from PubChem, 20 ppm × 92.14 / 24.4 gives 75.5 mg/m3, which lines up with the 75 mg/m3 printed in the WEL list, and the monitoring contractor is briefed in both units before the line starts.

The same chemical may also carry a warning duty or a spill duty. The Prop 65 checker tells you whether a California label is due, and the RQ lookup gives the release quantity that has to be phoned in.

Frequently asked

What is an OSHA PEL?

A permissible exposure limit is the airborne concentration a worker may be exposed to under 29 CFR 1910.1000. Most Table Z-1 limits are 8 hour time weighted averages, and a limit printed with a "C" is a ceiling that must not be exceeded at any time. Substances such as benzene, formaldehyde and lead have their own standard elsewhere in Subpart Z, and the Z-1 row simply points to it.

Are OSHA PELs legally enforceable?

They are, because the limits in Tables Z-1, Z-2 and Z-3 are part of the regulation itself, which is why this tool reads them from the eCFR text and not from a guidance table. OSHA also publishes annotated PEL tables that set Cal/OSHA, NIOSH and ACGIH values beside the federal limit, and those other values are recommendations unless a state plan adopts them.

What is the difference between the Australian WES and the new WEL list?

Safe Work Australia is replacing the workplace exposure standards with workplace exposure limits. Its page says a business must comply with the WES list until 1 December 2026 and with the WEL list from that date. Many WEL values are lower, so the tool shows both lists side by side and labels which one is in force.

How do I convert ppm to mg/m3?

Multiply the ppm figure by the molar mass in g/mol and divide by the molar volume of air. Section 3.3 of the Safe Work Australia WES list uses 24.4 L at 25 degrees C and 101.3 kPa. OSHA states its ppm values at 25 degrees C and 760 torr, and the ideal gas volume at those conditions works out to 24.47 L, so the two answers differ by well under 1 percent.

Why does a CAS search sometimes miss an OSHA row?

Footnote (c) to Table Z-1 says the CAS number is for information only and enforcement is based on the substance name. Entries that cover a group, such as cyanides or fluorides, carry no CAS number at all, and metal compound entries carry the CAS number of the metal. Search by name as well when a CAS search comes back empty.

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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.