CAS 100-42-5 · TSCA · United States of America

Styrene (vinylbenzene) under TSCA

C8H8 · 苯乙烯

Status: Listed. Styrene is on the TSCA Inventory as a grandfathered pre-1979 substance and is currently listed as TSCA Active. **Active OSHA Styrene-specific provisions** under 29 CFR 1910.1000 Table Z-2 (PEL 100 ppm 8-hr TWA, 200 ppm acceptable ceiling, 600 ppm 5-min peak; verify against https://www.osha.gov/annotated-pels). **California Proposition 65 listed as a carcinogen since 22 April 2016** (verify exact listing date against OEHHA https://oehha.ca.gov/proposition-65/proposition-65-list before invoicing California-distributed product). **TRI Section 313 listed**: Form R annual reporting required. NOT on EPA RMP threshold list. NOT on DEA scheduling. EPA TSCA Section 6 risk evaluation: styrene was designated a high-priority substance in 2019 (verify current TSCA risk-evaluation status against https://www.epa.gov/assessing-and-managing-chemicals-under-tsca before relying on it). NO active US AD/CVD case on Chinese-origin styrene currently (verify against https://access.trade.gov/ before invoicing). Section 301 List 3 25% additional duty applies on HS 290250.

The US styrene lane is dominated by **OSHA Styrene-specific 29 CFR 1910.1000 PEL + Cal Prop 65 "WARNING" labelling (since 2016) + TRI Form R annual reporting + NESHAP 40 CFR 63 Subpart EEEEE for boat manufacturing + reinforced plastic composite operations** workplace + downstream + emission-source compliance overhead. **TSCA Section 6 high-priority designation since 2019** (risk evaluation work-pending; long-term watch-item). NO active US AD/CVD case. Section 301 List 3 25% additional duty applies. Major US producers: Americas Styrenics (Chevron Phillips Chemical / Trinseo JV), TotalEnergies, INEOS Styrolution, LyondellBasell. US is comparatively self-sufficient. **Benzene (batch 22) feedstock cost flow-through is dominant** (~70-80% of production cost). **Styrene distinguishing pattern in US lane**: heavier workplace + downstream compliance overhead than benzene batch 22 (NESHAP boat manufacturing layer is unique to styrene); IARC Group 2A reclassification 2018 drove Cal Prop 65 listing 2016.

Listing and threshold

Substance Styrene (vinylbenzene) (CAS 100-42-5), C8H8
Regime US Toxic Substances Control Act (TSCA), administered by EPA
Jurisdiction United States of America
Status Listed
Tonnage threshold CDR (Chemical Data Reporting) threshold: 25,000 lb (11,340 kg) manufactured or imported per site per year

Classifications under this regime

  • OSHA Hazard Communication Standard (HCS): GHS H226 / H315 / H319 / H332 / H361d / H372
  • OSHA PEL 29 CFR 1910.1000 Table Z-2: 100 ppm 8-hr TWA, 200 ppm acceptable ceiling, 600 ppm 5-min peak (per https://www.osha.gov/annotated-pels)
  • NIOSH REL: 50 ppm 8-hr TWA, 100 ppm STEL
  • **TSCA Section 6 prioritisation**: high-priority designation in 2019 but risk evaluation work-pending
  • NOT on TSCA Section 5(a)(2) Significant New Use Rule list
  • NOT on EPA RMP threshold list
  • NOT on DEA List I or List II
  • **California Proposition 65 listed as carcinogen since 22 April 2016** (verify against OEHHA https://oehha.ca.gov/proposition-65/proposition-65-list)
  • **TRI Section 313 listed**: Form R annual reporting required for facilities above thresholds
  • DOT hazardous materials regulation (49 CFR 172.101): UN 2055, Class 3, PG III
  • **IARC: Group 2A (probably carcinogenic to humans) since 2018**
  • NESHAP styrene emission standards (40 CFR 63 Subpart EEEEE) for boat manufacturing + reinforced plastic composite operations

Restrictions and conditions of use

  • TSCA Section 6 high-priority designation (2019) but risk evaluation work-pending; long-term watch-item
  • OSHA-compliant SDS and workplace HazCom training required
  • OSHA Styrene-specific 29 CFR 1910.1000 PEL compliance
  • **Cal Prop 65 listing requires "WARNING"** on consumer products containing styrene above No-Significant-Risk-Level
  • NO active US AD/CVD case on Chinese-origin styrene currently
  • Section 301 List 3 25% additional duty applies on Chinese-origin styrene (HS 290250)
  • NFPA 30 Flammable and Combustible Liquids Code applies for storage
  • **NESHAP 40 CFR 63 Subpart EEEEE**: styrene emission standards for boat manufacturing + reinforced plastic composite operations
  • TRI Form R annual reporting

Importer obligations

TSCA is a self-certification regime: importers attest at customs entry that the substance is on the TSCA Inventory. The dominant practitioner-facing layer for styrene is **OSHA Styrene-specific 29 CFR 1910.1000 PEL compliance + Cal Prop 65 "WARNING" labelling + TRI Form R annual reporting + NESHAP 40 CFR 63 Subpart EEEEE for boat manufacturing + reinforced plastic composite operations**. NO active AD/CVD case so no AD margin documentation. Section 301 List 3 25% additional duty applies. **TSCA Section 6 high-priority designation** (2019) means risk evaluation may begin; long-term watch-item. Major US domestic producers: Americas Styrenics (Chevron Phillips Chemical / Trinseo JV; Allyn Point Texas + St. James Louisiana), TotalEnergies (Carville Louisiana), INEOS Styrolution (Channelview Pasadena Sweeny Texas), LyondellBasell Channelview (Texas).

Required documents

  • TSCA Section 13 Import Certification statement on customs entry
  • OSHA-compliant SDS reflecting H226 / H315 / H319 / H332 / H361d / H372 classification
  • Customs entry CBP Form 7501 with HS code 290250 (styrene) and Section 301 List 3 25% duty applied
  • Cal Prop 65 "WARNING" label compliance documentation for consumer-product downstream applications
  • TRI Form R annual report (where site exceeds 25,000 lb manufacture / 10,000 lb other-use thresholds)
  • CDR filing every 4 years if site exceeds 25,000 lb/yr threshold (next cycle 2026)
  • NFPA 30-compliant storage tank engineering documentation for bulk receipt
  • NESHAP 40 CFR 63 Subpart EEEEE compliance for downstream boat manufacturing + reinforced plastic composite applications

Common compliance traps

The pitfalls that have bitten importers on this lane in the past. None of these is theoretical.

  • **TSCA Section 6 high-priority designation since 2019**; risk evaluation work-pending; long-term watch-item
  • **Cal Prop 65 listing applies to all finished-product distribution to California**
  • **TRI Form R annual reporting**
  • **NESHAP 40 CFR 63 Subpart EEEEE** for boat manufacturing + reinforced plastic composite operations
  • NO active US AD/CVD case on Chinese styrene currently
  • Section 301 List 3 25% additional duty applies; structurally lighter than caprolactam batch 14 + acetic acid batch 19 lanes
  • Major US domestic producers: Americas Styrenics (Chevron Phillips Chemical / Trinseo JV), TotalEnergies (Carville Louisiana), INEOS Styrolution (Channelview Pasadena Sweeny Texas), LyondellBasell Channelview
  • US is comparatively self-sufficient in styrene through domestic supply
  • **Benzene (batch 22) feedstock cost flow-through is dominant** (~70-80% of production cost): US benzene supply via reforming + steam-cracker pyrolysis-gasoline integrates economics

Where to read next

For substance-level identifiers (formula, molecular weight, SMILES, InChIKey), GHS hazard profile, IMDG transport class, and full sourcing reference for styrene (vinylbenzene), see the CAS 100-42-5 sourcing reference.

For grade-by-grade buying notes, freight maths, supplier-tier pricing, and a worked landed-cost example, the styrene (vinylbenzene) cornerstone hub covers the full sourcing chain.

For the structure and history of TSCA, see the TSCA glossary entry.

Need cross-jurisdiction compliance support on this substance? Run it through the REACH / TSCA / IECSC / AICIS / K-REACH checker, or send us the substance and the destination and we will quote FOB China and CIF / DDP landed including the regulatory work on the destination side.

Read next

Cross-jurisdiction profile and sourcing references

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