ST. PETERSBURG, Fla. (AP) — Carnival said Thursday it was spending about $400 million to clean up the air pollution from the massive diesel engines it uses to power more than 70 cruise ships.

The company said it had decided to invest more money and put the technology in more ships than initially planned. Last year, Carnival said it would deploy scrubbers to reduce sulfur dioxide and use filters to trap soot on as many as 32 ships over the next three years as part of an agreement reached with the Environmental Protection Agency.