Appendix A Revision – TIH Chemicals

As I have mentioned in a couple of different blog posts lately (here and here), the folks at DHS Infrastructure Security Compliance Division (ISCD, the CFATS people) have asked for comments about potential revisions to Appendix A, 6 CFR Part 27, the DHS list of chemicals of interest (COI). I’m going to start my look at Appendix A by looking at the Release-Toxic COI on the list  and what chemicals might be added to the list.

Background

The preamble to the Appendix A final rule defines the term ‘release-toxic’ as chemicals “with the potential to create a toxic cloud that would affect populations within and beyond the facility, if intentionally released”. Later DHS noted that it used the same EPA “listing criteria, including the EPA acute toxicity criteria and vapor pressure cut-off [10-mm Hg or greater]” used to establish the RMP list of toxic substances. DHS did remove three RMP toxic substances from the release-toxic list (the three toluene isocyanate isomer listings) because they did not meet the vapor pressure standards (EPA included them because of Congressional direction).

Interestingly (for reasons that will soon be obvious) the crafters of Appendix A turned to another regulatory agency for their definition of Theft/WME (weapons of mass effect), the another sort of toxic chemical covered by the CFATS regulations. Here they turned to DOT’s ‘gas poisonous by inhalation’ or Division 2.3. For Theft/WME DHS “listed all DOT Division 2.3 PIH gases including those in Hazard Zones A through D”.

Those Hazard Zones are a relative measure of the toxicity of the chemical based upon the LC₅₀ for the chemical. The LC₅₀ is the “concentration of vapor, mist, or dust which, administered by continuous inhalation for one hour to both male and female young adult albino rats, causes death within 14 days in half of the animals tested”. The hazard zones for Division 2.3 gasses are the same as those for Division 6.1 poisonous liquids.

Toxic Inhalation Hazard Chemicals

Of the 52 Release-toxic chemicals currently listed on the DHS COI list, seventeen are listed by DOT as Division 6.1 (poisonous material) chemicals {15 Division 2.3, 12 Class 8 (corrosive liquids), and 5 Class 3 (flammable liquids)}. Of those 17 listed in Division 6.1 twelve were listed in the two most deadly Hazard Zones (5 in Zone A; 7 in Zone B).

There are a total of 39 additional Division 6.1 chemicals listed in DOT’s 49 CFR 172.101 that also fall into Hazard Zones A and B. The reason that these chemicals do not fall under the RMP toxic definition is generally that these chemicals do not meet the ≥10mmHg vapor pressure standard used by EPA. In many cases this is because the vapor pressure is not publicly available (and as a production chemical veteran I assume that this is because no one has measured the vapor pressure, not a conspiracy to withhold information).

Now of the 17 chemicals on the EMP’s toxic list that are also included in DOT’s Division 6.1  five are found in Hazard Zone A and seven are in Hazard Zone B. The other five are of lower toxicity.

Proposal

I would like to propose that in the revised Appendix A that DHS list all 32 Division 6.1, Hazard Zones A and B chemicals not currently listed in Appendix A. The seven in Zone A (listed below) should be listed without condition due to their extreme toxicity (LC₅₀ < 200 ppm). Note: four of these chemicals (⁺) were not listed as Division 6.1 chemicals in 2007; additional testing by the Europeans revealed the extent of their toxicity since then and §172.101 has since been revised.

• tert-Butly isocyanate;

• Ethyl isocyanate⁺;

• Isobutyl isocyanate⁺;

• Isopropyl isocyanate⁺;

• Methoxymethyl isocyanate⁺;

• Methyl vinyl ketone; and

• n-Propyl isocyanate;

The remaining 25 in Hazard Zone B (listed below) should be listed unless their vapor pressure is < 10mmHg. Chemicals without readily available vapor pressure information would be provisionally listed in Appendix A until such time as an EPA accredited lab provided test data to show that their vapor pressure < 10mmHg. This provisional listing would provide manufacturers with a specific incentive to have the vapor pressure testing done. Currently the lack of RMP listing because of the lack of vapor pressure data acts as a disincentive to have the testing done.

• Allyl chloroformate;

• Bromoacetone;

• n-Butyl chloroformate;

• Chloroacetone;

• Chloroacetonitrile;

• 2-Chloroethanol;

• Chloropicrin;

• Cyclohexyl iscocyanate;

• 3,5-Dichloro-2,4,6-trifluoropyridine;

• Dikete;

• Dimethyl sulfate;

• Ethyl chloroformate;

• Ethyl phosphonothioic dichloride, anhydrous;

• Ethyl phosporodichloridate;

• Ethyldichloroarsine;

• Ethylene chlorohydrin;

• Ethylene dibromide;

• Hexachlorocyclopentadiene;

• Methanesulfonyl chloride;

• 2-Methyl-2-heptanethiol;

• Methyl iodide;

• Methyl isothiocyanate;

• Methyl orthosilicate;

• Methyl phospoonous dichloride;

• Methyldichloroarsine;

• Phenyl isocyanate;

• Phenyl mercaptan;

• Phenylcarbylamine chloride;

• Thiophosgene;

• Trimethoxysilane;

• Trimethylacetyl chloride;

NOTE: A copy of this blog was submitted to the Docket on 10-29-15 at 2:20 pm CDT