Also known as: Caswell No. 572A, EINECS 220-239-6, UNII-229D0E1QFA, MI, MIT
CAS 2682-20-4
2-Methyl-3(2H)-isothiazolone (CAS 2682-20-4) is a chemical substance with GHS signal word Danger; key hazard signal: H330; H311; H301; H314; H318; H317; H400; H410. Key regulatory status: REACH registered, 57 regulatory/inventory lists, cosmetic ingredient cross-reference; source data from ECHA CLP, EPA ToxValDB, EPA CPDat, AICIS, SCCS, ECHA REACH.
2-Methyl-3(2H)-isothiazolone is classified GHS Danger (H330, H311, H301, H314, H318, H317, H400, H410) in the chemicals database but is restricted in EU cosmetics at max 0.0015% in rinse-off cosmetics only; banned in all leave-on cosmetics.
CAS, identifiers, formula, and alternate names for the matched substance record.
EU harmonized hazard classification, hazard statements, pictograms, and signal word.
| Hazard Class | H-Statements | Pictograms | Signal |
|---|---|---|---|
| Acute Tox. 2; Acute Tox. 3; Acute Tox. 3; Skin Corr. 1B; Eye Dam. 1; Skin Sens. 1A; Aquatic Acute 1; Aquatic Chronic 1 | H330; H311; H301; H314; H318; H317; H400; H410 | GHS06; GHS05; GHS09 | Danger |
Industrial and product-use categories associated with this substance.
Inventory, screening, and regulatory list matches from public chemical databases.
| List | Keyword | Source |
|---|---|---|
| active_ingredient; Europe; Pesticides | Commission of the European Communities | CPCat |
| Arts and crafts/Office supplies - general arts and crafts supplies - arts and crafts paint; Europe | Danish Environmental Protection Agency | Danish EPA |
| Arts and crafts/Office supplies - general arts and crafts supplies - arts and crafts paint; Europe | Danish Environmental Protection Agency | Danish EPA |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | State of California | State of California |
| active_ingredient; Pesticides | California Department of Pesticide Regulation | State of California |
| CEDI | FDA | United States Food and Drug Administration (FDA) |
| Indirect additives food contact (10/2018) | FDA | United States Food and Drug Administration (FDA) |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| active_ingredient; Pesticides | MN Department of Agriculture Pesticide Sales Database | CPCat |
| drinking_water; Europe; manufacturing; plastic_additive | Belgaqua | CPCat |
| inert_ingredient; non_food_use; Pesticides | EPA | CPCat |
| SCIL (9/2019) | USEPA | Safer Chemical Ingredients List |
| detected; Other indirect contact consumer goods | Danish Environmental Protection Agency | Danish EPA |
| children; Europe; Personal care - general moisturizing - hand/body lotion | Danish Environmental Protection Agency | Danish EPA |
Toxicology endpoints rendered from public NOAEL study rows.
| Value | Unit | Endpoint | Route | Species | Source |
|---|---|---|---|---|---|
| 19 | mg/kg bw | - | oral | rat | Regulatory source |
| 28.6 | mg/kg bw/d | - | - | - | Regulatory source |
| 7.89 | ug/mL | CD54, EC200 | Dermal | - | NTP ICE skin sensitization |
| 4.594 | ug/mL | CD86, EC150 | Dermal | - | NTP ICE skin sensitization |
| 9 | ug/mL | CD86, EC150 | Dermal | - | NTP ICE skin sensitization |
| 9.23 | ug/mL | CD86, EC150 | Dermal | - | NTP ICE skin sensitization |
| 44.3 | ug/mL | CV70 | Dermal | - | NTP ICE skin sensitization |
| 24.7 | ug/mL | CV75 | Dermal | - | NTP ICE skin sensitization |
| 0.232 | % | Concentration, 5% incidence of positive responses | Dermal | Human | NTP ICE skin sensitization |
| 0.525 | % | Concentration, 5% incidence of positive responses | Dermal | Human | NTP ICE skin sensitization |
| 0.04 | % | Concentration, one positive response | Dermal | Human | NTP ICE skin sensitization |
| 0.05 | % | Concentration, one positive response | Dermal | Human | NTP ICE skin sensitization |
| =0.021 | mg/m3 | DNEL local | inhalation | Human | ToxValDB GESTIS DNEL |
| 97.9 | % | Depletion Cys | Dermal | - | NTP ICE skin sensitization |
| 100 | % | Depletion Cys | Dermal | - | NTP ICE skin sensitization |
| -5.6 | % | Depletion Lys | Dermal | - | NTP ICE skin sensitization |
| 1.1 | % | Depletion Lys | Dermal | - | NTP ICE skin sensitization |
| 46.15 | % | Depletion Lys + Cys | Dermal | - | NTP ICE skin sensitization |
| 51 | % | Depletion Lys + Cys | Dermal | - | NTP ICE skin sensitization |
| 11.78 | uM | EC1.5 | Dermal | - | NTP ICE skin sensitization |
| 0.37 | % | EC3 | Dermal | Mouse | NTP ICE skin sensitization |
| 1.9 | % | EC3 | Dermal | Mouse | NTP ICE skin sensitization |
| 2.2 | % | EC3 | Dermal | Mouse | NTP ICE skin sensitization |
| 29.56 | uM | EC3 | Dermal | - | NTP ICE skin sensitization |
| 1 | unitless | EPA Classification | Ocular | Rabbit | NTP ICE eye irritation |
| 2 | unitless | EPA Classification | Inhalation | - | NTP ICE acute inhalation |
| 3 | unitless | EPA Classification | Inhalation | - | NTP ICE acute inhalation |
| 1 | unitless | EPA classification | Dermal | Rabbit | NTP ICE skin irritation |
| 2 | unitless | EPA classification | Dermal | Rat | NTP ICE acute dermal |
| =2 | Unitless | EPA classification | oral | Rat (Female) | NTP ICE acute oral |
| 2 | unitless | EPA classification | Dermal | Rabbit | NTP ICE skin irritation |
| 3 | unitless | EPA classification | Dermal | Rat | NTP ICE acute dermal |
| =3 | Unitless | EPA classification | oral | Rat | NTP ICE acute oral |
| =3 | Unitless | EPA classification | oral | Rat (Female) | NTP ICE acute oral |
| 3 | unitless | EPA classification | Dermal | Rabbit | NTP ICE skin irritation |
| 4 | unitless | EPA classification | Dermal | Rat | NTP ICE acute dermal |
| 229D0E1QFA | UNII | FDA UNII substance identifier | - | - | openFDA substances |
| 1 | unitless | GHS Classification | Dermal | Guinea pig | NTP ICE skin sensitization |
| 4 | unitless | GHS Classification | Inhalation | - | NTP ICE acute inhalation |
| =3 | Unitless | GHS classification | oral | Rat (Female) | NTP ICE acute oral |
| =4 | Unitless | GHS classification | oral | Rat (Female) | NTP ICE acute oral |
| =4 | Unitless | GHS classification | oral | Rat | NTP ICE acute oral |
| 5 | unitless | GHS classification | Dermal | Rat | NTP ICE acute dermal |
| =5 | Unitless | GHS classification | oral | Rat (Female) | NTP ICE acute oral |
| 139 | uM | IC50 | Dermal | - | NTP ICE skin sensitization |
| 22.6 | ratio | Imax | Dermal | - | NTP ICE skin sensitization |
| 0 | % | Incidence of positive responses | Dermal | Human | NTP ICE skin sensitization |
| 0.4762 | % | Incidence of positive responses | Dermal | Human | NTP ICE skin sensitization |
| 0.8621 | % | Incidence of positive responses | Dermal | Human | NTP ICE skin sensitization |
| 10 | ug/cm2 | Induction dose per skin area | Dermal | Human | NTP ICE skin sensitization |
Showing 50 of 78 studies
Registration status from the ECHA REACH registered substances database.
| Status | Name | EC Number | Link |
|---|---|---|---|
| Registered | 2-methyl-2H-isothiazol-3-one | 220-239-6 | ECHA overview → |
Australian industrial chemicals inventory status and applicable conditions.
EU Scientific Committee opinions tied to the matched substance.
| Opinion | Date | Conclusion | Max Conc. | Concerns |
|---|---|---|---|---|
| SCCS/1557/15 | 15 December 2015 | not safe (leave-on products) | Safe only in rinse-off at 0.0015%; NOT safe in leave-on products | Potent sensitiser; high sensitisation rates in population; not safe in any leave-on product including wipes; even 0.0015% in rinse-off products needs further consideration |
| SCCS/1521/13 | 27 March 2014 | not safe (leave-on) | 0.0015% rinse-off only; NOT safe in leave-on | Strong contact allergen; rising sensitisation rates; leave-on products not safe at any concentration |
Same-CAS cosmetic ingredient record for cross-vertical context.
Same-CAS pharmaceutical records from drug and bioactivity sources.
Same-CAS cannabis compliance and lab records where available.
1 cannabis record found in efsa substances.
View full cannabis profile →2-Methyl-3(2H)-isothiazolone (CAS 2682-20-4) is classified under EU CLP Annex VI as Acute Tox. 2; Acute Tox. 3; Acute Tox. 3; Skin Corr. 1B; Eye Dam. 1; Skin Sens. 1A; Aquatic Acute 1; Aquatic Chronic 1 with signal word Danger. Hazard statements: H330; H311; H301; H314; H318; H317; H400; H410. Source: EU CLP Annex VI (ECHA).
2-Methyl-3(2H)-isothiazolone has 78 NOAEL studies in the database. The lowest reported value is -5.6 % via Dermal. Source: NTP ICE skin sensitization.
2-Methyl-3(2H)-isothiazolone appears on 21 regulatory/inventory lists including active_ingredient; Europe; Pesticides, Arts and crafts/Office supplies - general arts and crafts supplies - arts and crafts paint; Europe, active_ingredient; Pesticides, and 18 more. Source: EPA CPDat.
Yes, 2-Methyl-3(2H)-isothiazolone is also indexed as a cosmetic ingredient under the name Methylisothiazolinone. View the full cosmetic safety profile on the ingredient page for detailed safety data, SCCS opinions, and regulatory status.
Safety data is sourced from ECHA CLP Annex VI, EPA ToxValDB, EPA CPDat, AICIS (Australian Industrial Chemicals Introduction Scheme), EPA DSSTox, ECHA REACH, CosIng / Ingredients DB, ChEMBL / DailyMed, cannabis regulatory/lab databases. All data traces to primary regulatory sources and is updated from official government databases.
2-Methyl-3(2H)-isothiazolone is classified GHS Danger (H330, H311, H301, H314, H318, H317, H400, H410) in the chemicals database but is restricted in EU cosmetics at max 0.0015% in rinse-off cosmetics only; banned in all leave-on cosmetics.
2-Methyl-3(2H)-isothiazolone also appears in cosmetics, pharmaceutical, cannabis databases.