At a glance
| Chemical family | Polycyclic aromatic hydrocarbon (PAH) — three-ring structure |
| CAS number | 83-32-9 |
| Classification | IARC Group 3 (not classifiable as to carcinogenicity to humans); EPA Priority Pollutant |
| Where you encounter it | Coal tar, combustion products, tobacco smoke, diesel exhaust; used in manufacture of dyes, pigments, and some plastics |
| Sleep micro-environment relevance | Low concern. Present in household dust from combustion sources but at low levels and with low toxicological significance. Part of the broader PAH exposure panel |
Regulatory & certification status
| European Union | Not individually restricted under REACH for consumer articles. Water Framework Directive listed. Regulatory |
| United States | EPA Priority Pollutant. Clean Water Act listed. Regulatory |
| Canada | CEPA Schedule 1 as part of the PAH group. Regulatory |
| International | IARC Group 3 (not classifiable). One of the 16 EPA priority PAHs. Regulatory |
What it is
Acenaphthene is a three-ring PAH consisting of a naphthalene unit with an ethylene bridge. It is found in coal tar (approximately 0.3% of coal tar) and is produced during incomplete combustion. It has some industrial use as a raw material for the manufacture of acenaphthylene, naphthalic anhydride (used in dye production), and some pharmaceuticals. IARC classified acenaphthene as Group 3 in 2010. There is no significant evidence of carcinogenicity or genotoxicity. Its primary toxicological concern is mild skin and respiratory irritation at high concentrations.
Where it shows up in bedding
Acenaphthene is not used in bedding products. Its bedroom presence, when measurable at all, comes from the same combustion sources as other PAHs: tobacco smoke, wood smoke, and outdoor exhaust infiltration. Because acenaphthene is relatively volatile for a PAH, it dissipates from surfaces more quickly than the heavier PAHs and is less likely to accumulate in dust over time.
Citations
- IARC (2010). Some Non-Heterocyclic Polycyclic Aromatic Hydrocarbons. IARC Monographs Vol. 92. Source Peer-reviewed
- ATSDR (1995). Toxicological Profile for Polycyclic Aromatic Hydrocarbons (PAHs). Source Regulatory
- EPA. Acenaphthene — Priority Pollutant listing. Source Regulatory
Frequently asked questions
Is acenaphthene dangerous?
At the trace levels found in household dust, acenaphthene poses minimal risk. IARC classifies it as Group 3 (not classifiable as to carcinogenicity) and it is not considered genotoxic. It can cause mild skin and respiratory irritation at high occupational concentrations, but typical indoor levels are far below those thresholds.
How is acenaphthene different from acenaphthylene?
Acenaphthene (CAS 83-32-9) has an ethylene bridge between the two positions on the naphthalene ring, while acenaphthylene (CAS 208-96-8) has an ethylene double bond (vinyl bridge) in the same position. Both are lighter PAHs with low carcinogenic concern. Acenaphthylene is actually a dehydrogenated form of acenaphthene.
Related compounds
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Last reviewed 2026-07-07. If you find a factual error, contact us.