WASHINGTON In the wake of terrorist attacks in Iraq using chlorine-augmented, vehicle-borne improvised explosive devices, the U.S. Department of Homeland Security is paying closer attention to the production and shipment of chlorine in the U.S.

This could be of interest to some motorcoach operators because their bus yards and facilities may be in industrial areas where chlorine is manufactured and stored, or near rail and truck facilities where it is shipped.

So, consider this story something of a heads up.

The Department of Homeland Security says that most of the 11 million metric tons of chlorine produced in the U.S. is used at the site where it is manufactured. However, roughly 4 million metric tons is shipped throughout the country.

Chlorine is commonly used in water treatment and in the production of paper, plastics, dyes, textiles, medicines, antiseptics, insecticides, solvents and paints.

Chlorine is considered most vulnerable to theft and sabotage during shipment because it is a ubiquitous industrial chemical and travels with little or no physical security. It is transported in small cylinders, one-ton containers, railcars and tanker trucks.

The Department of Homeland Security says it has received a small number of reports of suspicious licensed truck drivers or student truck drivers seeking access to hazardous material shipments, including one who only wanted to transport chlorine.

Anyone witnessing suspicious or criminal activity near a chlorine production, storage or shipping facility should contact the FBI Joint Terrorism Task Force and/or the Department of Homeland Security National Operation Center.

FBI regional phone numbers can be found online at www.fbi.gov/contact/fo/fo.htm, and the NOC can be reached at (202) 282-8101, or by e-mail at NOC.Common@dhs.gov.