US Secretary of State John Kerry
U.S. Secretary of State John Kerry sits next to U.S. Senator Lisa Murkowski (R-Alaska) during the Arctic Council Ministerial Session at City Hall in Kiruna, Sweden, May 15, 2013. CReuters/Hans-Olof Utsi/Scanpix Sweden

(Reuters) - A U.S. senator from Alaska concerned about salmon fishing and tourism urged the State Department in a letter released on Monday to help ensure that Canadian metal mines are safe after a major spill of waste into waterways near the Alaska border.

Millions of gallons of gray sludge containing metals and minerals spilled into waterways last week from Imperial Metals Corp's Mount Polley gold and copper mine in British Columbia.

Fish and other aquatic life were not expected to be overly harmed by the breach of a dam at the mine, British Columbia's environment ministry said, but residents were told not to drink or bathe in the waterways and fishing was banned.

"The tailings breach ... has renewed the specter of environmental impacts from large-scale hard rock mineral developments in Canada that are located near transboundary rivers," Senator Lisa Murkowski, a Republican, said in a letter to Secretary of State John Kerry dated Aug. 8. The letter can be seen at ( 1.usa.gov/1sOVT8D ) .

Murkowski urged Kerry to push his Canadian counterparts to make sure oversight on existing mines was robust and that final reviews would be conducted on proposed projects.

The spill came at a time of weak global prices for metals, but British Columbia has plans for at least five mines.

Murkowski has criticized federal environmental restrictions on Pebble Mine, a large copper mine project in southwestern Alaska near Bristol Bay, saying the state should decide the project's fate.