The Trump administration is still soliciting bids for a wall between the U.S.-Mexico border — and California is still trying to make building that wall as difficult as possible.

California State Senator Ricardo Lara put forth an amended version of a bill on Monday that would prohibit state contractors from working with any company or person that participates in building Trump’s border wall.

“We’re not going to allow a wall that harms our environment and our economy,” Lara, a Democrat who represents Southeast Los Angeles County, said in a statement. The amended bill, which was introduced for the first time in December, is set for hearing by the Senate’s Governmental Organization Committee on April 25.

More than 700 companies and individuals submitted wall design proposals to the Center for Border Patrol, which put out a call for proposals in March. The CBP plans to select a limited number of companies to build prototypes of their proposed wall in 30-feet long segments, in San Diego. The San Diego region is one of the busiest entryways for border crossers entering the U.S.

Senate Bill 30 would prohibit the state from establishing or renewing a contract for goods or services with any of the companies selected, even if the company is based in California. At least three of the companies that publicly shared their proposals are based in San Diego.

“The border region is home to tremendous cultural history and economic commerce between the United States and Mexico,” the bill states. Building a wall would damage the state’s economy which heavily relies on trade with Mexico. The bill also states that over 200,000 jobs in California are supported by the state’s commercial relationship with Mexico, either through commerce, tourism or foreign direct investment from Mexico. Additionally, in 2015, nearly 20 percent of the state’s overall exports were to Mexico, amounting to over 26 billion dollars in commerce. A wall would also threaten the endangered species on the border.

Some of the companies who proposed wall designs have a different perspective. “The California senator may have a different opinion if he were to understand that the wall with Mexico could actually pay for itself,” Thomas Gleason, Managing Partner of Gleason Partners, told Vocativ last week. The Las Vegas-based company submitted a proposal for a wall made solely from slanting solar panels.

There are already around 650 miles of fencing along the 2,000 mile long border between Mexico and the U.S. According to an internal report by the Department of Homeland Security, a border wall would cost a total of $21.6 billion and take three and a half years to construct.