The U.S. Senate has blocked a bipartisan deal to end the 10-day-old partial shutdown of the Federal Aviation Administration.

Congress’ failure to reach a compromise Monday means the stalemate will likely continue through August, as Congress is expected to begin its month-long recess Tuesday.

The FAA has been partially shut down since July 22, after lawmakers failed to agree on an extension of its authority to operate.

Some 4,000 FAA employees have been furloughed. The shutdown has also affected construction projects that employ about 70,000 workers.

U.S. Transportation Secretary Ray LaHood says the shutdown is costing the government some $200 million a week in uncollected taxes on air fares. Congressional officials say that over $1 billion in uncollected revenues will be lost if Congress fails to resolve the standoff until the end of August.

Air travel in the United States is still safe, because the laid-off FAA employees are researchers or other types of workers not involved in day-to-day air travel.

Lawmakers failed to pass the funding for the FAA because of disputes between Democrats and Republicans on several issues, including a provision that would make it harder for airline and railroad workers to unionize. Another controversial provision would cut subsidies to airports in rural communities.