Classification of Ferrosilicon (30 to 90% Silicon)

This is in response to your August 8, 2006 letter requesting verification that a letter of interpretation issued on April 14, 1997 from Delmer F. Billings to Mr. William P. Roman (Ref. No.: 97-1025) regarding the classification of ferrosilicon as non-regulated under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) remains valid. You indicate that the ferrosilicon is manufactured by the same company, continues to contain between 30 and 90 percent silicon, and is identical in composition to the material identified in Mr. Roman's February 18, 1997 request for interpretation.

On May 6, 1997 we published a final rule under Docket HM-215B (62 FR 24690) which made editorial revisions to the classification criteria for Division 4.3 materials. The final rule removed the Division 4.3 classification testing requirements from Appendix E of the HMR and added a reference to the UN Recommendations on the Transport of Dangerous Goods Manual of Tests and Criteria (UN Manual) to § 173.124(c). However, the requirements contained in the UN Manual were and continue to be virtually identical to those contained in the HMR at the time the letter in question was drafted. Therefore, according to the information you provided, letter of interpretation 97-1025 remain valid.