I hope you’re not tired of hearing about Inherently Safer Technology (IST). While this is not a new discussion, it appears to be heating up now that CFATA of 2008 is moving out of its draft form. Chemical and Engineering News, an American Chemical society publication, has a short article about the conflicts between chemical manufacturers and the railroads about IST.
The article quotes Edward R. Hamberger, president and chief executive officer of the Association of American Railroads (AAR) as saying; “We can no longer continue to risk the lives of millions of Americans by using, transporting, and storing highly toxic chemicals when there are safer alternatives commercially available.”
In an earlier article on the AAR web site a press release urged Congress to take action:
“It's time for the big chemical companies to do their part to help protect America. They should stop manufacturing dangerous chemicals when safer substitutes are available. And if they won't do it, Congress should do it for them in the Chemical Facility Anti-Terrorism Act of 2008.”
Liability Reasons for Supporting IST
The railroads are concerned about their liability when they transport dangerous chemicals, particularly toxic by inhalation (TIH) chemicals like chlorine, anhydrous ammonia and sulfur dioxide. They do not have the choice of whether or not to carry such chemicals; they are required to carry all lawful cargo offered for transport. In the event of an accident or terrorist attack, however, they will face financial responsibility for the resulting injuries.
As the AAR put it in a Freight Railroad Security fact sheet on their web site, rail security legislation and legislation must:
“Address the ‘bet the company’ risk that railroads are forced to assume because of their common-carrier obligation to carry highly-hazardous materials. This can be done, either by limiting railroads’ liability in case of an accident or terrorist incident involving highly hazardous materials or by eliminating railroads’ common-carrier obligation to carry them.”
Of course, if the railroad could get out of carrying these TIH chemicals by having the government, in effect, outlaw the use of those chemicals, they also eliminate their liability. Unfortunately for the railroads, there is little likelihood that Congress could muster the support for the mandatory replacement of TIH chemicals; there are just too many uses where substitutes are not available, much less practical.
Replacing Chlorine with Bleach
The most common IST mentioned, both by the railroads and the Center for American Progress, is the use of bleach (sodium hypochlorite) instead of chlorine gas. This is actually misleading until you look at the more complete common name, chlorine bleach; this is simply another method for getting chlorine into the water. The big difference is that the chlorine is diluted and it is not longer considered a toxic by inhalation chemical.
Chlorine bleach is manufactured from chlorine gas. An increase in the amount of bleach used for water treatment means that current bleach manufacturing facilities will have to be expanded and/or the number increased. Since chlorine bleach is slightly less effective water disinfection agent (on the basis of the number of chlorine atoms employed to disinfect a gallon of water) more chlorine will be required to be converted into bleach than would be used in direct chlorine injection.
While chlorine bleach is not as toxic as chlorine gas, it does have its own special chemical hazards. At industrial concentrations chlorine bleach is toxic and corrosive to skin, eyes and lungs. It also explosively reacts with a wide variety of chemicals, including a number found at water treatment facilities. The reactions typically release enough energy to catastrophically split a storage tank and releases chlorine gas. Extensive procedures and precautions need to be put into place to prevent the unintended mixing of chlorine bleach and these chemicals.
Since chlorine bleach is simply a diluted method of delivering chlorine it takes a much larger volume of chlorine bleach to deliver the same amount of chlorine. This means that there are more loads of hazardous chemicals transported and more handling steps involved. Not only is more transportation energy required, but there are an increased number of chances for an accident or handling mistake to be made. And chlorine gas will still be transported to the producers of the bleach.
Obtaining the Benefits of IST
As I have said on a number of occasions, inherently safer technologies will certainly (by definition) reduce the risk of both accidental and terrorist releases of dangerous chemicals. One does have to take a close look at replacement chemicals to ensure that they are actually inherently safer. Substituting a lower risk for a high risk is goodunless you are actually increasing the total risk.
Substituting chlorine bleach for chlorine gas actually increases the risk on the rail system. A larger amount of chlorine gas will be transported to a smaller number of destinations; that may be a good thing. But, in addition to that, there will be a much larger amount of slightly less hazardous material added to the transportation mix. The total risk to the railroad system will be increased.
Actually implementing real IST programs will be much more complicated and involved. A good example is the program described in congressional hearings last month. Kevin Wattier of the Long Beach Water Department described the efforts of his department to replace chlorine gas shipments with on site generated chlorine gas. The chlorine is transported in an inherently safe form, sodium chloride or table salt, and then split into caustic soda and chlorine gas by using electricity.
The Long Beach Water Department facility has been working on this conversion for a number of years and still has some time to go before their conversion is complete. When it is complete they will have only very small amounts of chlorine gas on hand at any one time. They will have the benefits of chlorine gas disinfection while eliminating most of the security and safety issues. This is truly an IST project.
Implementing IST is seldom simple. It takes a great deal of thought, planning and money to properly effect an increase in safety. Requiring companies to implement an IST program within 180 days is unrealistic and is a sure way to increase the total risk in the system.
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