Benzisothiazolinone (BIT)CAS 2634-33-5
The "MIT-free" replacement that's still an isothiazolinone — different sensitization profile, same chemistry family.
Toxic Chemical Databases
Substance-specific listings — these flags are for Benzisothiazolinone alone, not for the broader family.
Chemical Type
Isothiazolinone Preservative
Chemical Description
BIT is a structural variant of MIT — benzene-fused ring instead of methyl. It shares the same biocidal mechanism and the same risk of skin sensitization, but the cross-reactivity profile is different: a person sensitized to MIT may or may not react to BIT, and vice versa. Manufacturers reformulated to BIT after MIT restrictions and labeled products "MIT-free" — true on the label, but BIT-sensitized patients are now appearing in dermatology clinics at rising rates. EU REACH SVHC listed BIT as a skin sensitizer in 2020.
Biological Activity
Severity scores specific to this substance, NOT the parent family average. Differences between siblings are real and meaningful.
Top Health Consequences
- Skin sensitization (separate from MIT cross-reactivity)
- REACH SVHC Candidate List entry for sensitization
- "MIT-free" claims often still contain BIT
- Allergic contact dermatitis with chronic exposure
Pathways of Exposure
- Inhalation during latex paint application
- Dermal contact with treated water-based products
- House dust from treated wallpaper and adhesives
Building Materials with Benzisothiazolinone
Listed alphabetically — product categories where this specific substance appears.
Latex Paint Preservation ("MIT-Free" Lines)
Leather Treatment Preservation
Sealant & Caulk Preservation
Water-Based Construction Adhesives
How We Keep Benzisothiazolinone Out of a House
Benzisothiazolinone is one of the substances our screening is built to catch. A healthy home is won in the specification and the submittal review, long before anyone opens a bucket on site.
If you want a house specified this way from the start, or an existing house assessed for what is already in it, that is the work we do. Earth Bound Homes builds in San Jose, Los Gatos, Santa Clara County and across the San Francisco Bay Area.