OECD Corrosion Guidlines

This is in response to your letter of August 12, 1998, requesting information on the determination of whether a material meets the definition for a Class 8 (corrosive) material under the Hazardous Materials Regulations (HMR; 49 CFR parts 171-180). Specifically, you ask whether you may use the OECD guidelines (which require evaluation for 72 hours) to determine if a material is corrosive or if evaluation for 14 days is required to determine corrosivity for Packing Group II and III materials as provided by § 173.137. Your questions are paraphrased and answered as follows:

Q. Should the OECD guidelines be followed with the observation time extended to 14 days regardless of whether the material has shown full reversibility within a timespan of less than 14 days?

A. The OECD guidelines were adopted in the HMR to provide the method to determine whether a material meets the criteria for a Class 8 hazardous material. For purposes of classification under the HMR evaluation of up to 14 days is required for Class 8 materials in Packing Groups II and III as provided by § 173.137. However, if a material causes full thickness destruction of intact tissue in less than 14 days no further observation is necessary.

Q. When classifying a material as corrosive or non-corrosive is the OECD method acceptable with an endpoint observation of 72 hours?

A. The answer is no. For classification purposes of the HMR observation of up to 14 days is required.