---
kind: "section"
citation: "49 C.F.R. § 173.136"
title: "49"
number: "173.136"
heading: "Class 8—Definitions."
url: "https://uscodex.org/cfr/49/173.136"
---

# §173.136. Class 8—Definitions.

- (a) For the purpose of this subchapter, “corrosive material” (Class 8) means a liquid or solid that causes irreversible damage to human skin at the site of contact within a specified period of time. A liquid, or a solid which may become liquid during transportation, that has a severe corrosion rate on steel or aluminum based on the criteria in [§ 173.137(c)(2)](/cfr/49/173.137.md?p=c-2) is also a corrosive material. Whenever practical, in vitro test methods authorized in [§ 173.137](/cfr/49/173.137.md) of this part or historical data authorized in [paragraph (c)](#c) of this section should be used to determine whether a material is corrosive.
- (b) If human experience or other data indicate that the hazard of a material is greater or less than indicated by the results of the tests specified in [paragraph (a)](#a) of this section, PHMSA may revise its classification or make the determination that the material is not subject to the requirements of this subchapter.
- (c) Skin corrosion test data produced no later than September 30, 1995, using the procedures of [part 173](/cfr/49/part173.md), appendix A, in effect on September 30, 1995 (see [49 CFR part 173](/cfr/49/part173.md), appendix A, revised as of October 1, 1994) for appropriate exposure times may be used for classification and assignment of packing group for Class 8 materials corrosive to skin.

## Notes

### Amendments

[Amdt. 173-224, 55 FR 52634, Dec. 21, 1990, as amended at 56 FR 66270, Dec. 20, 1991; Amdt. 173-234, 58 FR 51532, Oct. 1, 1993; Amdt. 173-241, 59 FR 67508, Dec. 29, 1994; Amdt. 173-261, 62 FR 24732, May 6, 1997; 69 FR 76155, Dec. 20, 2004; 71 FR 78631, Dec. 29, 2006; 76 FR 3372, Jan. 19, 2011; 85 FR 27880, May 11, 2020]

### Source

Source: Amdt. 173-224, 55 FR 52634 Dec. 21, 1990, unless otherwise noted.

### Authority

Authority: 49 U.S.C. 5101-5128, 44701; 49 CFR 1.81, 1.96 and 1.97.

### Amendments

[Amdt. 173-224, 55 FR 52634, Dec. 21, 1990, as amended at 56 FR 66270, Dec. 20, 1991; Amdt. 173-234, 58 FR 51532, Oct. 1, 1993; Amdt. 173-241, 59 FR 67508, Dec. 29, 1994; Amdt. 173-261, 62 FR 24732, May 6, 1997; 69 FR 76155, Dec. 20, 2004; 71 FR 78631, Dec. 29, 2006; 76 FR 3372, Jan. 19, 2011; 85 FR 27880, May 11, 2020]