Missouri Attorney General Chris Koster filed a suit this week against California, claiming a state farming law violates the commerce clause of the U.S. Constitution and encroaches on Missouri sovereignty.

Koster's complaint stems from California voters' passage of Proposition 2 in 2008 and the subsequent passage in 2010 by the California State Assembly requiring other states to comply with the proposition, according to a news release.

In 2008, California passed a law prohibiting farmers in the state from using several agricultural production methods Koster said are in widespread use throughout the rest of the country. For example, starting in 2015, California egg producers are required to comply with new rules regulating the size of enclosures surrounding egg-laying hens.

The California State Assembly's 2010 ruling requires egg producers in other states, including Missouri, to comply with Proposition 2 when selling their eggs in California, the release said.

The lawsuit alleges the California law violates the federal commerce clause, which prohibits states from enacting legislation regulating conduct beyond its borders or protecting its own residents from out-of-state competition, according to Koster.

“California has placed restrictions on the sale or transfer of a commodity based on production methods that have nothing to do with the health or safety of California consumers,” Koster said in the release. “If California legislators are permitted to mandate the size of chicken coops on Missouri farms, they may just as easily demand that Missouri soybeans be harvested by hand or that Missouri corn be transported by solar-powered trucks.”

Of the 1.7 billion eggs laid per year by Missouri's 7 million egg-laying hens, roughly 540 million eggs are sold to California consumers. If forced to comply with California's law, Koster claims Missouri egg producers will face an estimated $120 million in capital improvement costs and a 20 percent increase in ongoing production costs.

"This case is not merely about farming practices,” Koster said. “At stake is whether elected officials in one state may regulate the practices of another state’s citizens who cannot vote them out of office.

"When California passes legislation that imposes new requirements or limits on Missouri businesses, it is my job to fight against it.”