Washington ? The government is quietly shipping stocks of antidotes against chemical weapons to states under a long-awaited program to boost response to a potential terrorist attack.

New York and Boston, sites of the upcoming political conventions, are among the first areas to receive the “chem-packs.”

Within two years, the Centers for Disease Control and Prevention will try to disperse allotments to every state.

“It’s a quick way for hospitals to know they’ll have the antidotes they need,” Donna Knutson, CDC’s deputy director of terrorism preparedness, said Tuesday in an interview with The Associated Press.

The program was begun in part because there had been “an uneven level of protection across the country,” added Steve Adams, deputy director of the Strategic National Stockpile Program.

Much of the nation’s efforts to prepare for terrorism have focused on biological attacks. For example, the National Pharmaceutical Stockpile contains tons of drugs, vaccines and other medical supplies in storage around the country, so that any U.S. city could receive an emergency shipment within 12 hours.

That’s probably plenty of time to react to an incubating infection like anthrax, but the ability to survive a chemical attack depends on immediate decontamination and rapid administration of appropriate antidotes.

Yet the antidotes are expensive and have fairly short shelf lives, making them hard for many states to keep stocked.

Enter the chem-packs, which CDC began shipping four months ago.

The gurney-sized packs come with an assortment of antidotes to the many chemicals available to a terrorist; atropine to fight nerve agents, for instance, or amyl nitrite for cyanide. Some are in autoinjectors for use at the site of an attack, others packaged for emergency-room use.

The CDC won’t say which states have received how many chem-packs so far, for security reasons, but did confirm that New York and Boston received shipments earlier than initially planned because of the approaching Republican and Democratic conventions.

The number distributed depends upon each state’s population, and state health departments decide which hospitals will store chem-packs.