Companies looking to help build Donald Trump’s border wall may face stiff penalties if lawmakers in several key markets have their way, especially in California.

Already in San Francisco’s Bay Area, lawmakers have proposed or passed legislation that would penalize companies that bid on the 2,000-mile Mexican border wall, as part of a resistance strategy to hobble its construction.

Two San Francisco city supervisors are introducing legislation Tuesday that would prevent the city from employing companies that are trying to secure contracts to help build the wall, regardless of whether their application is successful. And Democratic state assemblyman Phil Ting proposed legislation that would give the state’s public employee and retirement systems to liquidate any assets in businesses that contract with the Trump administration to build the wall.

More than 20 Bay Area companies have reportedly expressed interest in contracting for the wall project, according to the East Bay Express, and about 100 of the roughly 600 companies reportedly interested in bidding are based in California.

“What we are saying is that we are not going to spend billions of dollars and line the pockets of businesses that engage in work that goes against the values that we hold most dear,” San Francisco City Supervisor Hillary Ronen said in a San Francisco Chronicle report.

In neighboring Oakland, the City Council on Tuesday will formally vote on a proposal for a citywide boycott of companies looking to contract with the Trump administration.

The resolution was introduced by council member Abel Guillén last month and passed unanimously by the City Council Finance Committee.

And last week, Berkeley officials voted unanimously to divest from any business that get involved with the construction of the wall.

“Californians build bridges not walls,” Ting said in a statement. “This is a wall of shame, and we don’t want any part of it.”

Lawmakers elsewhere are mulling similarly punitive measures against would-be wall contractors. A statewide boycott of those companies was proposed by New York Assemblywoman Nily Rozic in January. Chicago state representative Will Guzzardi also proposed a bill that would divest pension funds and investments from companies working on the border wall. Neither of those measures have come up for votes yet. But by the time they do, it could be too late.

On Friday, U.S. Customs and Border Protection set deadlines for companies to submit design proposals, along with some guidelines. They are asking for two separate proposals: one for a solid concrete wall, and a second for the “other border wall” which will have a “see-through component/ capability.”

Bidders must submit a proposal for the concrete wall by Wednesday, and a proposal for the second wall by March 29.

There are parameters: CBP wants a wall design “physically imposing in height,” ideally 30 feet high, but it will consider proposals at a minimum height of 18 feet.