# 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo- — US federal chemical regulatory reporting thresholds by program (CERCLA, EPCRA, CAA)

For 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo-, cas no. is 56-04-2; cercla rq (lbs) is 10; rcra waste number is U164; regulatory categories is 4, verified against its source on 2026-08-05.

- **Substance:** 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo- _(verified: appears in the quote below)_
- **CAS No.:** 56-04-2 _(verified: appears in the quote below)_
- **CERCLA RQ (lbs):** 10 _(verified: appears in the quote below)_
- **RCRA waste number:** U164 _(verified: appears in the quote below)_
- **Regulatory categories:** 4 _(verified: appears in the quote below)_

## What the source says

> 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo- | 56-04-2 | 4 | U164 | 10 (4.54)

## 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/).