Thousands of government workers could still be furloughed this month unless Congress and the White House agree on emergency salary money for their agencies.

To forestall furloughs Congress must either override President Reagan's veto of the supplemental appropriation bill -- with payroll money for cash-short agencies -- or approve a compromise supplement that the president will sign.

Pending a settlement, these agencies have issued possible furlough alerts:

National Aeronautics and Space Administration has 22,000 workers (more than 5,000 here) braced for up to 11 days' furlough starting next Thursday (Sept. 16).

About 30,000 at the Justice Department, including several thousand here, may be furloughed later this month. No starting date or number of furlough days has been announced.

Health and Human Services says 10-day furloughs (starting Sept. 16) are possible for 100,000 workers. HHS, with 30,000 people here, is one of the area's biggest employers.

IRS, after escaping this week's scare, could see 19,000 workers again facing the danger of a furlough next week.

General Accounting Office could have up to a 10-day furlough, starting Sept. 16 for 5,000 workers -- most of them in the Washington area.

Labor Department may be forced to furlough 6,000 people up to four days starting Sept. 27.

Selective Service may have to put 240 staff members on furlough Sept. 13, possibly running through the remainder of this month.

Federal Maritime Administration is braced for four days of furloughs for 180 workers.

Office of Personnel Management has scaled back its possible furlough days, but still may have to put 3,500 people on unpaid leave for up to four days beginning Sept. 27.

Department of Education may have to furlough 4,350 people for up to nine days.

Furloughs of up to four days may hit 219 employes at the National Transportation Safety Board.

Temporary layoffs are possible this month for some staff at the Secret Service, Office of Management and Budget and Executive Office of the President.

Some temporaries have already been hit at the Federal Emergency Management Administration, and 1,600 of its 2,200 workers face up to eight furlough days starting Sept. 21.