Rep. Markey has repeatedly expressed concern over potential use of chemicals like chlorine by terrorists and authored a provision, which is part of the 9/11 Commission Recommendation law signed by the president last August (PL 110-53), to require mandatory re-routing of security-sensitive materials such as chlorine to the safest and most secure rail route. In addition he has been a chief proponent of requiring chemical facilities to shift to safer chemicals or processes when feasible.

"This NYPD investigation has exposed a dangerous weakness in our homeland security defenses. The danger posed by chlorine is not a theoretical risk - there have already been several attacks using these materials in Iraq. Given what we know about this risk, it's outrageous that the investigators were able to purchase this toxic chemical online without even being asking for identification," said Rep. Markey.

According to a report by the Associated Press, NYPD investigators secretly set up a fictitious water-purification company last year in order to purchase large quantities of chlorine online.

"Inexpensive and simple alternatives exist for water purification purposes instead of highly toxic chemicals, substances which are tempting tools for terrorists. The United States should be moving quickly to switch over to the safer methods," added Rep. Markey.

Rep. Markey plans to addresses the issue of requiring validation for proposed imports, exports and domestic sales of materials like chlorine that could be used to make chemical weapons, as the House Homeland Security Committee considers legislation to increase chemical facility security. Rep. Markey authored a provision restricting the sale of materials that could be used to make a dirty bomb in the 2005 Energy Bill (P.L. 109-58).