# Hydroquinone — US federal chemical regulatory reporting thresholds by program (CERCLA, EPCRA, CAA)

For Hydroquinone, cas no. is 123-31-9; cercla rq (lbs) is 100; regulatory categories is 3, verified against its source on 2026-08-05.

- **Substance:** Hydroquinone _(verified: appears in the quote below)_
- **CAS No.:** 123-31-9 _(verified: appears in the quote below)_
- **CERCLA RQ (lbs):** 100 _(verified: appears in the quote below)_
- **Regulatory categories:** 3 _(verified: appears in the quote below)_
- **EPCRA TPQ (lbs):** 500/10,000 _(per ecfr.gov, not stated by the source above)_
- **EPCRA RQ (lbs):** 100 _(per ecfr.gov, not stated by the source above)_

## What the source says

> Hydroquinone | 123-31-9 | 3 | | 100 (45.4)

## What ecfr.gov says

> 123-31-9 | Hydroquinone | f | 100 | 500/10,000 |

Source: https://www.ecfr.gov/current/title-40/chapter-I/subchapter-J/part-355

## Source

- https://www.ecfr.gov/current/title-40/chapter-I/subchapter-J/part-302/section-302.4
- https://www.ecfr.gov/current/title-40/chapter-I/subchapter-J/part-355

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/).