Federal Communications Commission operations would grind to a halt if there’s a funding lapse because of a partial government shutdown.

Most of the FCC’s estimated 1,450 employees on board before a shutdown would be furloughed if there’s a funding lapse, according to an agency shutdown plan from September.

A funding lapse that lasts for more than a few days could slow FCC proceedings, such as its reviews of broadcast ownership rules, the T-Mobile US Inc.-Sprint Corp. merger, and Nexstar Media Group Inc.'s bid to acquire Tribune Media Co., said Gigi Sohn, a former Democratic FCC official.

The commission could be forced to push back filing deadlines—and pause its shot clocks for merger reviews—to account for missed work days.

“During a shutdown like this, aside from emergency personnel, nobody can work,” Sohn said. “It’s illegal to work. It’s illegal to use government email and answer the phone.”

The FCC hasn’t yet released official shutdown plans. An agency spokeswoman referred requests for comment on a potential shutdown to the White House’s Office of Management and Budget. The OMB didn’t immediately respond to a request for comment.

Almost all agency activities would likely be suspended, including answering consumer complaints, consumer protection and local competition enforcement, and broadcast, wireless and wireline licensing services, according to the agency’s September shutdown plan. FCC officials also wouldn’t be available to manage airwave spectrum or authorize new telecom equipment.

FCC Chairman Ajit Pai told reporters last week that agency officials were reviewing plans in case of a shutdown.

If reserve funds remain on hand from previous fiscal years, the FCC could stay open for a time after current funding lapses. The commission had enough reserve funding to remain open and pay staff for a week during a brief government shutdown in January.

If the FCC goes into shutdown, employees would have four hours to halt agency business, including canceling travel plans and meetings and placing out-of-office messages on email and voicemail.

A workforce of 243 employees would have remained at work under the September plan. Most of the retained employees, including Pai and the three commissioners, would have still been able to work because their salaries aren’t funded by annual appropriations. Other retained employees were assigned to spectrum auction-related activities, and to emergency safety to protect life and property.