California Portland Cement, which employs 140 people in Colton, California, says the economy has put the plant’s future in doubt.

The CalPortland plant is one of 11 California cement plants that is being required to upgrade to curb CO2 emissions.

But the company says the plant’s future is now uncertain. The recession has sent cement prices plunging, lowered profits and forced CalPortland’s drivers to cut back on hours. And the company says it faces new expenses: the cost of meeting California’s new requirements that manufacturers take steps to curb emissions of carbon dioxide.

State regulators have projected that retrofitting the state’s 11 cement plants would cost US$220m and reduce CO2 emissions by 12 per cent per ton of cement. But CalPortland’s executives say it would cost more than that to retrofit the Colton plant alone.

“We don’t have enough limestone left to invest $200 million,” said James A. Repman, the company’s president.

California was one of the first states to enact legislation to tackle global warming, with legislators passing a 2006 measure to curb carbon dioxide emissions in all economic sectors, including manufacturing, transportation and real estate development. But the state is also providing a lesson in how contentious carrying out such a law can be, especially at a time of economic crisis.

What happens in California — and in other states that have taken steps to reduce emissions — is being closely watched in Washington, where lawmakers will soon debate federal climate legislation. The Obama administration has said it plans to push for a cap-and-trade bill this year.