SHERIDAN, Wyo. (AP) — Fluoride is now being added to the water supply for the city of Sheridan.

The Sheridan Press reports that city Public Works Director Nic Bateson says fluoride is now being added to the water supply for city and Sheridan Area Water Supply customers.

The addition of fluoride began on Monday at both the Big Goose and Sheridan water treatment plants. Bateson says it will cost customers about 9 cents extra per month.

In 1950, Sheridan became one of the first U.S. cities to fluoridate its water in an effort to fight tooth decay. The city abandoned the practice after a 1953 referendum opposing fluoridation.