Polycyclic aromatic hydrocarbon

Indeno[1,2,3-cd]pyrene in the bedroom

By — 19-year firefighter and entrepreneur. Published July 2026.

Indeno[1,2,3-cd]pyrene is a five-ring PAH classified by IARC as Group 2B (possibly carcinogenic to humans, Monographs Vol. 92, 2010). It is one of the 8 PAHs restricted in consumer articles under EU REACH Annex XVII Entry 50. As a high-molecular-weight PAH, it is predominantly particle-bound rather than volatile — meaning it associates with particulate matter in air and dust rather than existing as a free vapour. In the bedroom, indeno[1,2,3-cd]pyrene is found in combustion-derived dust from diesel exhaust, tobacco smoke, and wood burning.

Indeno[1,2,3-cd]pyrene — Embr Bedroom Chemistry Atlas

At a glance

Chemical familyPolycyclic aromatic hydrocarbon (PAH) — five-ring high-molecular-weight structure
CAS number193-39-5
ClassificationIARC Group 2B (possibly carcinogenic to humans, Monographs Vol. 92, 2010). EU CLP Carc. 1B (H350). One of the 8 EU REACH Entry 50 restricted PAHs
Where you encounter itDiesel exhaust; tobacco smoke; coal and wood combustion; coal tar; predominantly particle-bound in air; household dust from combustion sources
Sleep micro-environment relevanceFound in household dust as a particle-bound PAH from combustion sources. Less volatile than lighter PAHs — exposure is primarily through dust particles rather than air. Contributes to cumulative PAH cancer risk

Regulatory & certification status

European UnionCLP Carc. 1B (H350). REACH Annex XVII Entry 50 restricts 8 priority PAHs (including IcdP) to 1 mg/kg in rubber and plastic components with prolonged skin contact. Regulatory
United StatesEPA Priority Pollutant. Clean Water Act listed. Not specifically restricted in consumer products beyond ambient criteria. California: listed under Proposition 65 as a carcinogen (effective 1988). Regulatory
CanadaCEPA Schedule 1 (toxic substance) as part of the PAH group. Regulatory
InternationalIARC Group 2B (possibly carcinogenic, Monographs Vol. 92, 2010). One of the 8 EU priority PAHs restricted in consumer articles. Regulatory

What it is

Indeno[1,2,3-cd]pyrene (IcdP) is a five-ring PAH with a molecular weight of 276 g/mol. Its high molecular weight means it is almost entirely associated with particulate matter in the environment — it does not exist as a free vapour under ambient conditions. IARC classified IcdP as Group 2B in Monographs Vol. 92 based on sufficient evidence of carcinogenicity in animals and inadequate evidence in humans. The EU classifies it as Carc. 1B under CLP. IcdP is produced during incomplete combustion and is found in diesel exhaust, tobacco smoke, coal tar, and wood smoke. It is commonly measured as part of the EPA priority PAH panel and the EU Entry 50 restricted PAH group.

Where it shows up in bedding

Indeno[1,2,3-cd]pyrene is not used in bedding products. It enters bedrooms bound to particulate matter from combustion sources: diesel exhaust from outdoor traffic that infiltrates indoors, tobacco smoke residue on surfaces and in dust, and fireplace or wood stove emissions. Because IcdP is particle-bound, it accumulates in settled dust rather than remaining airborne. During sleep, exposure occurs primarily through ingestion and dermal contact with contaminated dust, rather than inhalation of vapours. Regular cleaning to reduce dust accumulation is the most effective way to reduce exposure.

The Embr Exposure Ledger: Indeno[1,2,3-cd]pyrene

One chemical, several public questions, answered from independent datasets and joined here — the environment it shows up in, the body burden it carries, how it is regulated, and what actually reduces it.

This compound appears in 6 of the Embr Exposure Ledger’s 10 exposure datasets.
Is it in smoke?
Measured in the emissions of residential wood smoke. This is what the source gives off, not a level in anyone's home: it says the compound is present in that smoke, not how much of it reaches a person. What smoke leaves behind indoors.Source: US EPA, SPECIATE 5.4 — the EPA repository of source-emission composition profiles (air toxics, criteria and greenhouse pollutants)
At what level would it matter?
Published benchmarks exist: a residential indoor-air screening level of 0.017 µg/m³, set on a cancer endpoint (1-in-a-million excess lifetime risk). A screening level is the concentration at which EPA would look further, not a boundary between safe and harmful. The ledger holds no measured sleeping-environment concentration for this compound, so there is nothing here to compare the benchmark against — it tells you what would matter, not what is in any room.Source: US EPA, Regional Screening Levels (RSL) Summary Table — consolidated toxicity values from IRIS, PPRTV, ATSDR, Cal EPA and OPP
Who releases it?
313 Canadian facilities have reported it (2000-2024). These are self-reported quantities leaving a facility, not levels anyone encountered, and the two national programs are not added together — they use different reporting thresholds.Source: US EPA, Toxics Release Inventory (TRI) Basic Data File, 2024 reporting year; Environment and Climate Change Canada, National Pollutant Release Inventory (NPRI), releases 1993-present
Does the law flag it?
Listed under California Proposition 65 for cancer since 1988.Source: California OEHHA Proposition 65 List (Safe Drinking Water and Toxic Enforcement Act of 1986)
What reduces it?
Portable HEPA air cleaner, run continuously during a smoke episode — Cut indoor PM2.5 by 48-78% in seven homes during a 2020 wildfire episode; a systematic review of landscape-fire interventions puts portable air cleaners at 54-92% for PM2.5.Source: Xiang J et al. (2021). Field measurements of PM2.5 infiltration factor and portable air cleaner effectiveness during wildfire episodes in US residences. Science of the Total Environment.

Detection and body-burden figures are occurrence data, not a personal measurement or a health diagnosis. Part of the Embr Exposure Ledger — an open, cross-dataset chemical join (download the data), reusable with attribution.

Citations

  1. IARC (2010). Some Non-Heterocyclic Polycyclic Aromatic Hydrocarbons. IARC Monographs Vol. 92. Source Regulatory
  2. ATSDR (1995). Toxicological Profile for Polycyclic Aromatic Hydrocarbons (PAHs). Source Regulatory
  3. EU REACH Annex XVII, Entry 50 — PAHs in consumer articles. Source Regulatory

Frequently asked questions

  • Why is indeno[1,2,3-cd]pyrene particle-bound?

    Its high molecular weight (276 g/mol) and low vapour pressure mean it does not evaporate into the air at ambient temperatures. Instead, it adsorbs onto the surface of particulate matter — soot, dust, and other fine particles generated during combustion. This means exposure is primarily through contact with or ingestion of contaminated particles rather than breathing vapours.

  • Is indeno[1,2,3-cd]pyrene in my mattress?

    No. IcdP is not a mattress material. If it is present in your bedroom, it comes from combustion-derived dust — outdoor diesel exhaust that infiltrates through windows, tobacco smoke residue, or fireplace/wood stove emissions. Reducing these sources and regular dust cleaning are the most effective controls.

Related compounds

  • Benzo[a]pyrene — the most potent common carcinogenic PAH
  • Chrysene — another REACH Entry 50 restricted PAH
  • Fluoranthene — one of the most abundant environmental PAHs
  • Pyrene — a four-ring PAH exposure marker

Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.

Last reviewed 2026-07-08. If you find a factual error, contact us.