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Maleic Anhydride

A polyester-resin precursor and aggressive respiratory sensitizer.

Building products and consumer items that commonly contain Maleic Anhydride
Common building materials and consumer products containing Maleic Anhydride

Toxic Chemical Databases

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

LBC Red List
Listed
Prop 65
Not Listed
IARC
Not Listed
NTP RoC
Not Listed
GSPI
Not Listed
REACH SVHC
Watch
TSCA
Listed

Chemical Type

Reactive Acid Anhydride

Chemical Description

Maleic anhydride is a small, reactive ring molecule that opens up in the presence of moisture to release maleic acid. It's a backbone ingredient in unsaturated polyester resins — the resin in fiberglass-reinforced plastic panels, simulated-stone countertops, and cultured-marble bath fixtures — and it's also used as a modifier in alkyd paints, automotive coatings, and adhesion-promoter additives. Even at low airborne concentrations maleic anhydride dust is a potent respiratory sensitizer: a single high-exposure event can trigger an asthma-like response that returns with every subsequent encounter. EBH avoids maleic-anhydride-based simulated-stone products and prefers unfilled solid surfaces or natural stone for countertops where possible.

Chemical Structure

Molecular schematic for Maleic Anhydride — formula and structural features shown below.

O O O
Maleic anhydride — C₄H₂O₃ · five-membered ring with two carbonyls and one oxygen bridge

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.

Respiratory
9/10
Immune
8/10
Skin
8/10
Cancer
3/10
Reproductive
3/10
Developmental
3/10
Endocrine
2/10
Neurological
3/10
Liver/Kidney
4/10
Cardiovascular
3/10

Chemical Analogs and Brand Names

Top Health Consequences

Pathways of Exposure

Building Materials with Maleic Anhydride

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

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.