Is Benzisothiazolinone safe in cosmetics?
Benzisothiazolinone has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
Benzisothiazolinone
Also known as: Caswell No. 079A, Caswell No. 513A, EINECS 220-120-9, EPA Pesticide Chemical Code 098901, UNII-HRA0F1A4R3 (+5 more)
INCI: BENZISOTHIAZOLINONE
Benzisothiazolinone (CAS 2634-33-5) is a cosmetic preservative functioning as Preservative; biocide. NOAEL 69 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max Permitted in rinse-off cosmetics; restricted or banned in leave-on products. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 2634-33-5 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
Benzisothiazolinone is classified GHS Danger (H302, H315, H317, H318, H400, H410, H411) in the chemicals database but is restricted in EU cosmetics at max Permitted in rinse-off cosmetics; restricted or banned in leave-on products.
Source: Cosmetics: ingredients.eu_status/eu_max; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Preservative; biocide
Safety Rating
MODERATE
Regulatory Status
EU EU Status
restricted
EU Max Conc.
Permitted in rinse-off cosmetics; restricted or banned in leave-on products
US US Status
permitted
US Notes
Permitted; EPA-registered biocide. Early sensitization signals emerging in patch-test clinical surveillance as use volume increases following MI restrictions.
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Benzisothiazolinone.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Benzisothiazolinone. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =15 mg/kg/day | oral | rat | repeated dose toxicity | SCCNFP_vision_codex |
| NOAEL | =15 mg/kg/day | oral | rat | repeated dose toxicity | SCCNFP_vision_codex |
| NOAEL | =15 mg/kg/day | oral | rat | repeated dose toxicity | SCCNFP_vision_codex |
| NOAEL | =15 mg/kg/day | oral | rat | repeated dose toxicity | SCCNFP_vision_codex |
| NOAEL | =0.018 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.018 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.018 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =0.018 mg/kg bw/d | oral | rat | dermal absorption | SCCS_vision_codex |
| NOAEL | =8.42 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =8.42 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCS_vision_codex |
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Benzisothiazolinone across SCCS product categories, with measured dermal absorption where available.
Sensitization Profile
Contact sensitization data for Benzisothiazolinone based on clinical patch test studies and IFRA standards.
Sensitization Rate
very-high
Allergen Class
preservative
EU Allergen Listed
no
Patch Test Positive Rate
10.4%
Cross-reactivity Group
isothiazolinone-group
Reaction Type
contact-dermatitis
Source: NACDG 2021-22; ESSCA 2019/20
EPA ToxValDB — Toxicity Values
10 toxicity values from EPA ToxValDB (aggregated from CCTE, HPV, ToxRefDB, IRIS, and other regulatory dossiers).
| Endpoint | Value | Species | Route | Duration | Source |
|---|---|---|---|---|---|
| LD50 | >2000 mg/kg | Rat | dermal | - | ECHA IUCLID |
| LD50 | >2000 mg/kg | Rat | dermal | - | ECHA IUCLID |
| LD50 | =454 mg/kg | Rat | oral | - | ECHA IUCLID |
| LD50 | =670 mg/kg | Rat | oral | - | ECHA IUCLID |
| LD50 | =490 mg/kg | Rat | oral | - | ECHA IUCLID |
| LOAEL | =20 mg/kg-day | Dog | oral | subchronic | ECHA IUCLID |
| NOAEL | =150 mg/kg-day | Rat | oral | short-term | ECHA IUCLID |
| NOAEL | =5 mg/kg-day | Dog | oral | subchronic | ECHA IUCLID |
| NOAEL | =69 mg/kg-day | Rat | oral | subchronic | ECHA IUCLID |
| NOAEL | =112 mg/kg-day | Rat | oral | - | ECHA IUCLID |
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Danger
Pictograms
Acute ToxicityCorrosiveEnvironmental Hazard
Hazard Class and Category
Acute Tox. 2; Acute Tox. 4; Skin Irrit. 2; Eye Dam. 1; Skin Sens. 1A; Aquatic Acute 1; Aquatic Chronic 1
Hazard Statements
- H330 Fatal if inhaled
- H302 Harmful if swallowed
- H315 Causes skin irritation
- H318 Causes serious eye damage
- H317 May cause an allergic skin reaction
- H400 Very toxic to aquatic life
- H410 Very toxic to aquatic life with long lasting effects
Specific Concentration Limits / M-factors
inhalation: ATE = 0.21 mg/L dusts or mists; oral: ATE = 450.0 mg/kg bw; Skin Sens. 1A; H317: C ≥ 0.036%; M = 1; M = 1
Inserted via ATP: ATP21
Sensitization AOP Dashboard
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
DPRA Cys %
97.7%
DPRA Lys %
9.7%
KeratinoSens IC50
50.87 µM
hCLAT CV75
1.83 µg/mL
LLNA EC3
4.8%
NESIL
1200 µg/cm²
LLNA: Moderate (1B)
GHS: 1B
Source: LLNA: Botham et al. (1991) | Gerberick et al. (2005); DPRA: Nukada et al. 2013 [DOI:10.1016/j.tiv.2012.11.006] | Gerberick et al. 2007 [DOI:10.1093/toxsci/kfh213]; KS: Emter et al. 2010 [DOI:10.1016/j.taap.2010.03.009]; hCLAT: Ashikaga et al. 2010 [DOI:10.1177/026119291003800403]
Endocrine Disruptor Evidence (Expanded)
Cross-referenced EDC classifications, mechanism data, and dose-response evidence from EDLists, SIN List, and cosmetic-specific detail sources.
Under investigation
Evidence: Limited
(2026)
Health effects: Yes
Affected pathways: Thyroid
Regulatory framework: BPR
Source list: II
Dose-Response Data Points
| Endpoint | Target | Value | Direction |
|---|---|---|---|
| Thyroid hormone levels (T3/T4 ↓); tshβ↑, deio2↓ | Thyroid axis (TR / deiodinase / TSH feedback) | EC50/IC50: LOEC = 30 µg/L (zebrafish T3/T4 decrease); LOEC: 30 µg/L; NOEC: not established mixed | thyroid disruptor |
| ERα / AR binding or transactivation | ERα / AR | EC50/IC50: No published EC50 for ER/AR; SCCS opinion focused on skin sensitization; LOEC: not reported; NOEC: not reported mixed | not assessed in published ER/AR assays (data gap) |
| AhR transactivation | AhR | EC50/IC50: No AhR data published for BIT at sub-cytotoxic concentrations; LOEC: not established; NOEC: N/A mixed | not active (data gap; BIT thyroid data stronger) |
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
10 - 100 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Aggregated DA Values (2 records across 5 sources)
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured | 61.9% | - | - | SCCS/0099 |
| measured | 42.05% | - | - | SCCS/0099 |
Additional Ingredient Properties
3 property records from structured ingredient metadata.
allergen_detail
{"eu_allergen_listed": "no", "allergen_class": "preservative", "cross_reactivity_group": "isothiazolinone-group", "patch_test_frequency_pct": "10.4", "sensitization_rate": "very-high", "common_reaction_type": "contact-dermatitis", "ifra_restricted": "no", "source": "NACDG 2021-22; ESSCA 2019/20"}
pregnancy_detail
{"pregnancy_safe": "avoid", "breastfeeding_safe": "avoid", "trimester_restriction": "all", "risk_category": "not-rated", "reason": "Sensitizer; isothiazolinone class concern", "alternative_ingredient": "Phenoxyethanol", "source": "EU regulation"}
uv_stability
{"uv_stable": "yes", "uv_degradation_rate": "stable", "photosensitizer": "no", "phototoxic": "no", "photoallergic": "no", "requires_uv_protection_packaging": "no", "color_change_uv": "no", "odor_change_uv": "no", "efficacy_loss_uv_pct": "0", "spf_contribution": "no", "uva_protection": "no", "uvb_protection": "no", "photostable_sunscreen": "no", "boost_spf_of_others": "no", "antioxidant_under_uv": …
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Binder
Biocide
Degradant/impurity
Fragrance
Preservative
Processing aids not otherwise specified
Regulatory List Membership (3)
IFRA Fragrance Transparency List
EPA Safer Chemical Ingredients List (SCIL)
FDA Indirect Food Contact Additives
Expert Verdict
Expert safety assessment and concern-level summary for Benzisothiazolinone.
Regulatory Flags
preservative
isothiazolinone
emerging-sensitizer
mi-replacement
intimate-wipe-caution
cross-reactivity-risk
surveillance-watch
epa_safer_alternative
ifra_fragrance
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Benzisothiazolinone by CAS number or substance name.
Studies
29
Lowest NOAEL
0.018
Highest NOAEL
4115
Units vary across source rows: mg/kg bw/day, mg/kg bw/d, mg/kg bw
ToxValDB_ECHA_IUCLID
SCCS_vision_codex
SCCNFP_vision_codex
Dermal Absorption
View details ->| Absorption % | Method | Vehicle |
|---|---|---|
| 61.9% | - | - |
| 42.05% | - | - |
Known Synonyms
Caswell No. 079A
Caswell No. 513A
EINECS 220-120-9
EPA Pesticide Chemical Code 098901
UNII-HRA0F1A4R3
1,2-Benzisothiazoline-3-one
2,3-dihydro-3-oxo-1,2-benzisothiazole
BIT
IPX
benzo[d]isothiazol-3-one
Chemical Function
Preservative
Antioxidant
Regulatory Lists
fracking; water
consumer_product; Europe
IFRA Transparency
SCIL (9/2019)
Europe; Pesticides
detected; Europe; Pesticides
Indirect additives food contact (10/2018)
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
ChEMBL ID
CHEMBL297304
Frequently Asked Questions
Is Benzisothiazolinone allowed in the EU?
Benzisothiazolinone EU regulatory status: restricted. Maximum allowed concentration: Permitted in rinse-off cosmetics; restricted or banned in leave-on products. This is based on EU Regulation 1223/2009 and its amendments.
What does Benzisothiazolinone do in cosmetics?
Benzisothiazolinone functions as: Preservative; biocide. It is classified as a Preservative in our database. CAS number: 2634-33-5.
What is the NOAEL for Benzisothiazolinone?
The NOAEL (No Observed Adverse Effect Level) for Benzisothiazolinone is =15 mg/kg/day based on a repeated dose toxicity study via oral route in rat. A total of 10 study endpoints are available. Source: SCCNFP_vision_codex.
Is Benzisothiazolinone used outside cosmetics?
Benzisothiazolinone also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does Benzisothiazolinone have different safety status in cosmetics vs industrial chemicals?
Benzisothiazolinone is classified GHS Danger (H302, H315, H317, H318, H400, H410, H411) in the chemicals database but is restricted in EU cosmetics at max Permitted in rinse-off cosmetics; restricted or banned in leave-on products.
Compliance Tools
Check Benzisothiazolinone compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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