New TIH Chemicals

I was working on a article this weekend for the next issue of the Journal of Hazmat Transportation about the public comments PHMSA had received on their HM-215K NPRM to harmonize the US Hazardous Materials Regulation (HMR) with the various modal international regulations. As a matter of course I had to review the NPRM closely, more closely than I had when it was published back in August.

As part of that review I noted that PHMSA is proposing to change the hazard classification of a number of existing chemicals to toxic inhalation hazard, Division 6.1.This proposed change is based on recent changes to the Revised 16th edition of the UN Model Regulations which was based upon a UN literature review. This would mean that those chemicals should be reviewed by DHS for possible inclusion in Appendix A as release toxic chemicals of interest (COI). This is a timely bit of information as I understand that DHS has a process underway to update Appendix A.

Three of the chemicals being changed in HM 215K are already on the Appendix A list:

• Tetranitromethane [Release Flammable COI]
• Phosphorous oxychloride [Release Toxic and Theft CW/CWP COI]
• Titanium tetrachloride [Release Toxic, Theft WME, Sabotage COI]

Two of the chemicals are actually already Division 6.1 TIH materials, but are having their relative risk elevated to PG I, the highest safety risk rating:

• Chloroacetonitrile
• Thiophosgene

The remaining chemicals are:

• Ethyl isocyanate [Flammable to TIH]
• Isobutyl isocyanate [Flammable to TIH]
• Isopropyl isocyanate [Flammable to TIH]
• Methacrylonitrile, stabilized [Flammable to TIH]
• Methoxymethyl isocyanate [Flammable to TIH]
• Sulfur chloride [Corrosive to TIH]

This change has not actually been made yet, as the public comment period for this NPRM was just completed last month. There were no comments received on the change of classification of these chemicals, so the change will almost certainly be included in the final rule when it is published, possibly as soon as later this year.

It is interesting to note that a number of these chemicals are industrial chemicals in use in a wide variety of industries. I would suspect that many of the facilities using these chemicals already use other COI that would have required submission of a Top Screen, but certainly not all of them.