Several cruise lines have been found to be in violation of Alaska air pollution regulations.

The Juneau Empire reports the violations were revealed Friday in Norwegian Cruise Line’s quarterly Security and Exchange Commission filing. Recent SEC filings also indicate that the Alaska Department of Environmental Conservation in April 2015 cited Royal Caribbean International and Celebrity Cruises for alleged violations.

The major cruise lines have allegedly violated the Alaska Marine Vessel Visible Emission Standards, which concern the opacity of visible emissions from ships within three miles of shore.

DEC spokeswoman Candice Bressler says the state has found 49 violations involving 19 different vessels between 2010 and 2014.

Norwegian Cruise Line and Royal Caribbean say they are working with the state of Alaska on the matter.

Photo Credit: The Norwegian Star in Alaskan waters. Tom Mascardo / Flickr