Chloroprene

The neoprene-rubber building block — a likely human carcinogen.

Common building materials and consumer products containing Chloroprene

Toxic Chemical Databases

Where this family lands across the seven independent toxicology authorities we screen against.

LBC Red List

Listed

Prop 65

Listed

IARC

Listed

NTP RoC

Listed

GSPI

Not Listed

REACH SVHC

Listed

TSCA

Listed

Chemical Type

Halogenated Diene Monomer

Chemical Description

Chloroprene is the chlorinated butadiene molecule that, once polymerized, becomes neoprene — the rubber you find in EPDM membrane adhesives, foam underlayments, wetsuit-style gaskets, and weatherproofing strips. EPA's IRIS program reclassified chloroprene as a likely human carcinogen, citing inhalation cancer risks near manufacturing facilities at concentrations far lower than older regulatory limits assumed. Cured neoprene products in a finished home pose much less hazard than the raw monomer, but residual unreacted chloroprene and breakdown products can off-gas for months. EBH avoids chloroprene-based adhesives and gaskets when butyl rubber, EPDM, or silicone alternatives can meet the same spec.

Chemical Structure

Molecular schematic for Chloroprene — formula and structural features shown below.

Chloroprene — CH₂=CCl−CH=CH₂ · C₄H₅Cl · the chlorinated cousin of butadiene

Biological Activity

Severity scores summarize hazard endpoints from IARC, NTP, EPA IRIS, ATSDR, and NIOSH on a 0–10 scale. Mirrors the system-level output of our SDS Toxic Chemical Screener.

Cancer

9/10

Respiratory

8/10

Liver/Kidney

7/10

Reproductive

6/10

Developmental

6/10

Neurological

5/10

Endocrine

4/10

Cardiovascular

4/10

Skin

6/10

Immune

5/10

Chemical Analogs and Brand Names

Chloroprene (2-chloro-1,3-butadiene) — CAS 126-99-8
Polychloroprene (neoprene polymer) — CAS 9010-98-4
C

Top Health Consequences

Lung, liver, and lymphatic cancers documented in human exposure cohorts
Chronic respiratory irritation and reduced lung function
Liver enzyme elevation with chronic inhalation exposure
Reproductive effects observed in animal models
Skin sensitization on direct contact with uncured product

Pathways of Exposure

Inhalation of solvent fumes from neoprene contact cement during installation
Off-gassing from new gaskets, weatherstripping, and roofing membranes
Dermal contact with uncured neoprene foam products
Background exposure from urban air near rubber-manufacturing facilities

Building Materials with Chloroprene

Listed alphabetically. These are the product categories where this chemistry most often shows up — not an exhaustive list.

Carpet Backing & Underlayment
Contact Cements & Construction Adhesives
Door & Window Gaskets
EPDM & Modified Bituminous Roofing Adhesives
Flexible Hoses & HVAC Connectors
Foam Pipe Insulation
Heat-Resistant Wire Insulation
Pool & Spa Liners
Vibration-Damping Pads
Weatherstripping & Seal Profiles

Want to screen a specific product? Drop the manufacturer's SDS into our SDS Toxic Chemical Screener — it runs every CAS number on the sheet against all seven databases shown above.