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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #16-0037 ([US Zinc] [Mr. John Williams])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: US Zinc

Individual Name: Mr. John Williams

Location State: MD Country: US

View the Interpretation Document

Response text:

Mr. John Williams
Director of HSE
US Zinc
2727 Allen Parkway, Suite 800
Houston, TX 77019

Ref. No.: 16-0037
This is in response to your email dated March 1, 2016, concerning the applicability of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) to the transportation of zinc dust that does not meet the test criteria for Division 4.3.
Depending on the properties of the material, zinc dust may be described, as appropriate, as "UN1436, Zinc powder or Zinc dust, 4.3, PG I, II or III", " UN3077, Environmentally hazardous substance, solid, n.o.s., 9, PG III", or as not regulated. The test method and criteria for classifying a material as Division 4.3 are contained in § 173.124(c). If the material evolves flammable or toxic gases when in contact with water, to the extent that it meets the prescribed criteria it would be classed as Division 4.3.  Based on the test results you submitted on zinc dust, we agree that this particular tested material does not meet the Division 4.3 criteria.
Based on the data you provided, the diameter of the zinc particles is less than 100 micrometers (0.004 inches), if the quantity in one package, or transport vehicle if not packaged, equals or exceeds 1000 pounds (the reportable quantity for zinc listed in Appendix A to § 172.101), the material would be regulated as a hazardous substance (see § 171.8).  If the material does not equal or exceed the reportable quantity and does not meet the criteria for any other hazard class or division then it is not subject to the HMR.
I hope this answers your inquiry.  If you need additional assistance, please contact the Standards and Rulemaking Division at (202) 366-8553.

Duane A. Pfund
International Standards Coordinator
Standards and Rulemaking Division

Regulation Sections

Section Subject
171.2 General requirements
172.204 Shipper's certification
173.35 Hazardous materials in IBCs