# 1,3,4-Metheno-2H-cyclobuta[cd]pentalen-2-one, 1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro- — US federal chemical regulatory reporting thresholds by program (CERCLA, EPCRA, CAA)

For 1,3,4-Metheno-2H-cyclobuta[cd]pentalen-2-one, 1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro-, cas no. is 143-50-0; cercla rq (lbs) is 1; rcra waste number is U142; regulatory categories is 1,4, verified against its source on 2026-08-05.

- **Substance:** 1,3,4-Metheno-2H-cyclobuta[cd]pentalen-2-one, 1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro- _(verified: appears in the quote below)_
- **CAS No.:** 143-50-0 _(verified: appears in the quote below)_
- **CERCLA RQ (lbs):** 1 _(verified: appears in the quote below)_
- **RCRA waste number:** U142 _(verified: appears in the quote below)_
- **Regulatory categories:** 1,4 _(verified: appears in the quote below)_

## What the source says

> 1,3,4-Metheno-2H-cyclobuta[cd]pentalen-2-one, 1,1a,3,3a,4,5,5,5a,5b,6-decachlorooctahydro- | 143-50-0 | 1,4 | U142 | 1 (0.454)

## Source

- https://www.ecfr.gov/current/title-40/chapter-I/subchapter-J/part-302/section-302.4

Last verified: 2026-08-05. Review by: 2027-08-05.
Part of [US federal chemical regulatory reporting thresholds by program (CERCLA, EPCRA, CAA)](https://referencesource.org/chemical-regulatory-reporting-thresholds/).