Monday, June 16, 2008

Extent of the PIH ‘Problem’

There have been a number of discussions on this blog about the problems posed by the rail shipments of Poisonous by Inhalation Hazard (PIH) or Toxic by Inhalation Hazard (TIH) chemical (different names for the same thing). There has been input by readers and I have not been shy about expressing my opinions. Recently I have been reviewing comments on a new proposed rule for improving the safety of railcars used to ship PIH chemicals (see: "Comments on Rail Security and Safety Rules – 6-06-08"). Reading all of these comments has been very instructive.

Number of Shipments

There does not seem to be a single authoritative number on the shipments of PIH chemicals. Looking at the statements from the varying producers of chlorine, anhydrous ammonia and other PIH chemicals, the number is much larger than even I imagined. And to make matters more interesting, not all of the manufacturers have filed comments, relying on industry groups to represent their views on this rule.

Where PIH Chemicals are Used

Many advocacy groups have rallied around the inherently safer technology (IST) banner, demanding that users shift from PIH materials to safer chemicals. Their standard example has always been the water treatment plants switching from chlorine to bleach. Looking at the statements filed shows that the wide variety of uses of PIH chemicals makes the IST look like a very long-term project.

Agriculture uses huge amounts of anhydrous ammonia. One producer, CF Industries, reports that their 26% of market share in the Corn Belt states alone accounts for 850,000 tons of anhydrous ammonia. While their individual customers are probably low-threat targets, their manufacturing plants, 10 terminals and 550 railcars may be high-risk targets. Additionally, they use anhydrous ammonia in their own production of phosphate fertilizers and ship anhydrous ammonia to coal fired power plants where it is used to scrub exhausts of a variety of potential pollutants.

Other PIH uses are reported:

  • BASF Corporation reports that they have 228 Ethylene Oxide railcars in service. EO is a chemical intermediate used in the production of a wide variety of industrial and commercial chemicals.
  • The Institute of Makers of Explosives reports that their member companies maintain a 1500 rail car fleet for shipping anhydrous ammonia, used in making ammonium nitrate, a component in 85% of all commercial explosives.
  • E.I. du Pont de Nemours and Company ships ten different commodity PIH chemicals. These include chlorosulfonic acid (CSA), dimethyl sulfate (DMS), anhydrous hydrogen fluoride (AN HF), anhydrous hydrochloric acid (AN HCl), hydrogen cyanide (HCN), oleum, sulfur trioxide (SO3), and titanium tetrachloride (TiCl4).
  • Arkema, Inc. ships 1000 rail cars of methyl mercaptan ever year. Methyl Mercaptan is used to make methionine, a component of animal feeds.
  • US Magnesium produces chlorine as a byproduct of their magnesium production process. If they were unable to ship chlorine they could not produce magnesium.
  • Occidental Chemical Corporation reports that they make 10,000 annual shipments of chlorine.

Pervasiveness of PIH Chemicals

These comments provide a window into how pervasive PIH chemicals are in industrial chemistry. Simplistic attempts to solve the problem by mandating shifts to ‘safer’ chemicals ignore the complexity of the problem. One thing in life is certain; a simple solution for a complex problem leads to too many more problems, and usually aggravates the original problem.

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