WASHINGTON — The Environmental Protection Agency is proposing tougher rules to reduce air pollution from large oceangoing ships, including oil tankers and cargo vessels.

The agency announced Wednesday it is beginning work on a regulation that would cut harmful chemicals releases from smokestacks of ships within 200 miles of the U.S. coast. The proposal would set tougher engine requirements and fuel standards for the large U.S.-flagged ocean going vessels

The United States also is negotiating with Canada over establishing coastal emission control zones. The EPA said the new proposed regulations and measures being worked out with Canada together are expected to cut nitrogen dioxide releases and soot pollution from large ships by 80 to 85 percent.