A federal agriculture agency is moving local operations and 40 jobs to Oakland and will leave San Francisco, while three regional governmental organizations have begun to scout for a single new headquarters in Oakland or San Francisco for nearly 500 employees, officials said Tuesday.

The U.S. Department of Agriculture has struck a deal to rent 18,000 square feet at 1333 Broadway in downtown Oakland. The deal was arranged through the federal General Services Agency and commercial realty firm Colliers International.

"USDA is relocating from San Francisco to Oakland," said Gene Gibson, a spokeswoman for the General Services Agency, which handles real estate requirements for an array of federal organizations. "About 40 people from the USDA will be working in the new office."

Separately, hundreds of workers for three regional government entities -- the Association of Bay Area Governments, the Metropolitan Transportation Commission and the Bay Area Air Quality Management District -- could be moving to new offices in either Oakland or San Francisco.

ABAG, MTC and the air quality district hope to find at least 150,000 to 200,000 square feet of offices in one building. That complex could contain the headquarters and principal operations of all three organizations, according to documents obtained Tuesday by Bay Area News Group.

"A new regional government facility" is how the documents describe the future complex. That would be the case if ABAG, MTC and the air quality district wind up in one location.

Oakland and San Francisco each stand to gain -- or lose -- hundreds of jobs if the three agencies follow through on these plans.

The new complex would be located in the Oakland or San Francisco market, according to MTC documents. The building would have to be close to a BART station.

At present, ABAG and MTC have their headquarters in Oakland. The Bay Area Air Quality Management District has its head offices in San Francisco.

Combined, the three agencies could transplant 477 workers to new offices on either side of the Bay. MTC has 200 employees, ABAG has 77 workers and the air quality district has 200 workers at its head offices.

The trio of government entities currently occupy a combined 149,000 square feet. The air quality district owns an 82,000-square-foot building on Ellis Street in San Francisco. At 101 Eighth St. in Oakland, MTC occupies 50,000 square feet and ABAG is in 17,000 square feet.

That means the future complex could be 33 percent larger than the combined office spaces the agencies now occupy at their respective headquarters.

"The air district is in quarters that are clearly substandard," said Randy Rentschler, an MTC spokesman. "As for MTC, we have maxed out on our space. We are a little bit squeezed. ABAG is in a similar situation. They are just running out of room."

The agencies often deal with similar issues such as transportation, development and environmental matters -- including new rules concerning greenhouse gases. They intend to choose a commercial realty brokerage to procure the new complex.

"The agencies prefer a purchase option over leasing," state the documents, which are a request for proposals from realty brokers.

Other government agencies are on the move in Oakland. The FBI recently decided to remain in downtown Oakland and will relocate its offices to 77,000 square feet at 2101 Webster St., three or four blocks from its current location.

As for the USDA, that agency is moving its Office of the Inspector General to downtown Oakland, Gibson said. The move should occur in the summer, she added.

The USDA relocation is a coup for Oakland, said Bill Nork, a broker with Cornish & Carey.

"This is a good sign that Oakland is getting some deals from outside of its market," Nork said. "If this ABAG, MTC and air district deal lands in Oakland, that would be great."

Contact George Avalos at 925-977-8477.