WASHINGTON – Wal-Mart Stores Inc. will pay a $1 million fine to resolve charges that it violated environmental laws while building stores in four states.

The chain, which builds more than 300 stores a year, also agreed Thursday to monitor future construction better. The Environmental Protection Agency said that could cost another $4.5 million.

“Those responsible for construction sites must control hazardous pollutants from flowing into drinking water sources and waterways,” EPA Administrator Christie Whitman said in a statement.