The government is worried about the safety of chemical facilities across the country after its power to keep dangerous substances out of the hands of extremists lapsed a month ago.

The Department of Homeland Security has long had the ability to inspect facilities where chemicals are used or stored to make sure their security systems are in place. And the facilities themselves have been required to vet prospective employees for any terrorism links.

But the program, called the Chemical Facility Anti-Terrorism Standards, expired July 28 after Congress failed to renew it. Homeland Security officials say this left gaping holes in the country’s national security, and they are calling on Congress to act quickly when it returns this week.