VOC exempt solvents like acetone and what the EPA list covers
VOC exempt solvents like acetone and methyl acetate are excluded from EPA's ozone VOC definition. What the exemption means, and why CARB rules differ.
VOC exempt solvents: the EPA list and what the exemption covers
VOC exempt solvents are organic compounds that a specific regulation leaves out of its VOC definition because they have negligible photochemical reactivity. Acetone, methyl acetate, methyl formate, dimethyl carbonate and propylene carbonate are all on the federal exempt list in 40 CFR 51.100(s).
The exemption is about ozone formation. It is not a finding of low volatility, no toxicity or no flammability, and it is not permission for every use. An EPA exemption also doesn't prove exemption under the California rule that covers your product.
Common solvents on the EPA VOC exempt list
The federal ozone-control definition covers carbon compounds that take part in atmospheric photochemical reactions, then lists exclusions. These five common solvents are excluded under 40 CFR 51.100:
| Solvent | Federal ozone-control VOC definition |
|---|---|
| Acetone | Excluded |
| Methyl acetate | Excluded |
| Methyl formate | Excluded |
| Dimethyl carbonate | Excluded |
| Propylene carbonate | Excluded |
The federal list also includes tert-butyl acetate, PCBTF and cyclic, branched or linear completely methylated siloxanes. These are federal classifications, not solvent recommendations. Check state and district rules separately.
Is acetone a VOC?
Chemically, yes. Acetone is a volatile organic compound, but section 51.100(s)(1) excludes it from the federal ozone-control VOC definition. Check the applicable product rule before excluding acetone from a VOC-content calculation: "acetone VOC content" depends on which rule you are reporting against. Acetone still evaporates from the product. The rule just doesn't count it as VOC.
What does CARB exempt mean?
The California Air Resources Board says exempt compounds are not expected to add meaningfully to ozone formation because of low atmospheric reactivity. A CARB exemption adds the compound to the list in the VOC definition of the applicable regulation, and only that one (CARB, VOC exemptions and reactivity).
CARB keeps separate consumer product regulations. Article 1 covers antiperspirants and deodorants, Article 2 general consumer products and Article 3 aerosol coatings (CARB current regulations). A spray cleaner is an aerosol, but it is not an aerosol coating. For architectural coatings, CARB's exemptions page points to a Suggested Control Measure. That measure is a model, not a binding coatings rule in every district.
CARB's 2021 amendment package took effect on August 1, 2022, when the Office of Administrative Law approved it. That is the package's effective date, not a product manufacture or sell-through deadline. Check the current compound list and category dates in the California Code of Regulations.
CARB's survey materials describe pre-regulatory work on prohibiting PCBTF, aimed at a 2027 hearing (CARB 2023 survey webinars). That is planning, not adopted law. Locally, South Coast AQMD amended Rule 1143, Consumer Paint Thinners and Multipurpose Solvents, on October 2, 2026 (SCAQMD Regulation XI). If you sell thinners or multipurpose solvents in that district, check the adopted rule before you pick a solvent.
Exempt does not mean unrestricted
Methylene chloride is on the federal VOC exempt list. But after November 22, 2019, TSCA rules prohibit manufacturing, processing and distributing it for consumer paint and coating removal (40 CFR 751.105). Other uses have their own restrictions (40 CFR 751.107, EPA methylene chloride risk management). An air rule and a chemical safety rule answer different questions.
Checks before you reformulate with an exempt solvent
- Name the jurisdiction and the exact rule: federal, CARB Article 1, 2 or 3, or a local air district rule.
- Confirm the product category, since limits and exemptions differ by category.
- Confirm the solvent is exempt in that rule's own VOC definition.
- Check separate restrictions, such as TSCA rules or a district prohibition.
- Check the test method and records. Under section 51.100(s)(2) and (s)(3), excluding an exempt compound from a measured result needs accurate quantification approved by the enforcement authority, and monitoring or testing can be required.
Aerosol coatings work differently. Under sections 51.100(s)(6) and (s)(7), every organic compound in the volatile portion counts toward the California and federal aerosol-coating reactivity-based limits. That includes acetone.
You can ask RegAffairs AI which solvents are VOC exempt and open the cited regulatory sources behind each answer.