CAS 106-99-0 · TSCA · United States of America

1,3-Butadiene under TSCA

C4H6 · 1,3-丁二烯

Status: Listed. 1,3-Butadiene is on the TSCA Inventory as a grandfathered pre-1979 substance and is currently listed as TSCA Active. **Active OSHA Butadiene Standard 29 CFR 1910.1051** (specific carcinogen standard with PEL 1 ppm 8-hr TWA, STEL 5 ppm, Action Level 0.5 ppm; verify against https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1051). **California Proposition 65 listed as carcinogen since 1 April 1988 and as developmental / male / female reproductive toxicant since 19 December 2003** (verify exact listing dates against OEHHA https://oehha.ca.gov/proposition-65/proposition-65-list before invoicing California-distributed product; some prior dataset references cited 1987 and 2001 dates). **TRI Section 313 listed**: Form R annual reporting required. **EPA RMP threshold: 10,000 lb** for flammable substance (verify current threshold against 40 CFR 68 Appendix A at https://www.ecfr.gov/current/title-40/part-68). NOT on DEA scheduling. NO active US AD/CVD case on Chinese-origin butadiene currently (verify against https://access.trade.gov/ before invoicing). Section 301 List 3 25% additional duty applies on Chinese-origin butadiene (HS 290124). EPA TSCA Section 6 risk evaluation: butadiene was previously prioritised but is currently not under active risk evaluation (verify TSCA risk-evaluation status against https://www.epa.gov/assessing-and-managing-chemicals-under-tsca). EPA NESHAP 40 CFR 63 covers butadiene emissions from synthetic organic chemical manufacturing (verify the applicable Subpart against https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-63 before relying on a specific subpart letter).

The US butadiene lane is dominated by **OSHA Butadiene-specific 29 CFR 1910.1051 PEL + Cal Prop 65 "WARNING" labelling (since 1987) + EPA RMP 10,000 lb threshold + TRI Form R annual reporting + NESHAP 40 CFR 63 Subpart F / G / H / I / U emissions standards** workplace + downstream + emission + RMP compliance overhead. NO active US AD/CVD case. Section 301 List 3 25% additional duty applies. Major US producers: TPC Group (Port Neches Texas; verify the most recent post-rebuild butadiene nameplate against the TPC Group corporate site before quoting world-largest single-site rank), LyondellBasell Channelview Texas, ExxonMobil Baytown + Beaumont, INEOS Channelview, Texas Petrochemicals. US is comparatively self-sufficient. **Butadiene distinguishing pattern in US lane**: heaviest workplace + downstream + upstream compliance overhead in dataset alongside benzene batch 22 + formaldehyde batch 18; butadiene-specific OSHA standard + EPA RMP threshold + Cal Prop 65 + TRI + NESHAP layered regulation.