Flavor ingredient regulatory record
Ethyl isothiocyanate
Ethyl isothiocyanate is a thiocyanate in the spice family, FEMA GRAS under FEMA number 4420 (CAS 542-85-8). Its odor is pungent, mustard-like, sharp, sulfurous.
- FEMA
- 4420
- CAS
- 542-85-8
- JECFA
- 1885
- Formula
- C3H5NS
GRAS status: FEMA GRAS, publication 23. Recorded by FDA in the Substances Added to Food inventory under CAS 542-85-8.
Structure
Identity
Also known as: Ethane, isothiocyanato-, Isothiocyanic acid, ethyl ester, Isothiocyanatoethane, Ethyl mustard oil, NSC 84212, Ethyl thioisocyanate, 1-Isothiocyanatoethane, isothiocyanatoethane, ethane, isothiocyanato-, ethylisothiocyanate, isothiocyanic acid, ethyl ester, isothiocyanato-ethane.
Can Ethyl isothiocyanate be labeled natural?
Ethyl isothiocyanate occurs in nature, so the label depends on the route: ethyl isothiocyanate won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized ethyl isothiocyanate is artificial. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
- United States
- Natural or artificial, by process
- European Union and UK
- Natural only from natural material
- Mercosur and Mexico
- Natural or identical-to-natural
How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.
Regulatory status, with citations
United States
Ethyl isothiocyanate is FEMA GRAS under FEMA number 4420. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
No EU FL number is on file for Ethyl isothiocyanate. That is not a finding either way. The Union List covers defined flavouring substances, so natural complex materials are handled as flavouring preparations under Parts B to F and never receive a number, and substances used as additives sit under Regulation 1333/2008 instead. Confirm the position before EU or UK use.
JECFA (WHO / FAO)
JECFA number 1885, evaluated at the 69th meeting in 2008. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. Ethyl isothiocyanate appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 542-85-8, where EPA names it Ethane, isothiocyanato-.
Active in US commerce
EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. What active and inactive mean.
EPA publishes no regulatory flags on this listing. What the flags mean.
From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.
Odor and taste
Odor: Pungent, mustard-like, sharp, sulfurous.
Where it is used
Ethyl isothiocyanate is used in seasoning, condiment, food preservation and snack foods, typically as a spice note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to Ethyl isothiocyanate by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| Isopropyl isothiocyanate | 4425 | 93% | In nature |
| Methyl isothiocyanate | 4426 | 70% | In nature |
| Hexyl isothiocyanate | 4422 | 68% | In nature |
| 2-Butyl isothiocyanate | 4419 | 67% | In nature |
| 5-(Methylthio)pentyl isothiocyanate | 4416 | 67% | In nature |
More thiocyanates in this index
Ethyl isothiocyanate FAQ
Does ethyl isothiocyanate have FEMA GRAS status?
Ethyl isothiocyanate holds FEMA GRAS status under FEMA number 4420. It is also codified at 21 CFR 172.515.
How do I cite ethyl isothiocyanate by FEMA or CAS number?
Cite ethyl isothiocyanate as FEMA 4420 or CAS 542-85-8; both point to the same entry. FEMA files it in the spice flavor category.
Can ethyl isothiocyanate be labeled a natural flavor?
Since ethyl isothiocyanate is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when ethyl isothiocyanate is synthesized. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
Is ethyl isothiocyanate approved in the EU?
No EU FL number is on file for ethyl isothiocyanate. It has a JECFA evaluation (JECFA 1885), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Has JECFA evaluated ethyl isothiocyanate?
Yes. JECFA number 1885, evaluated at the 69th meeting in 2008. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.
What does ethyl isothiocyanate smell and taste like, and where is it used?
The odor of ethyl isothiocyanate is pungent, mustard-like, sharp, sulfurous. Typical uses are seasoning, condiment, food preservation and snack foods.
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Guides: What Is FEMA GRAS? · Natural vs artificial · Filing a GRAS notification
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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as ETHYL ISOTHIOCYANATE under CAS 542-85-8 and carries its FEMA number, its JECFA flavor number. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.
A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.
Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.
About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.