CHARLESTON, W.Va. (AP) — The U.S. Department of Labor says natural gas drilling contractors have agreed to pay nearly $4.5 million in back wages to 5,310 natural gas workers in Pennsylvania and West Virginia. The department says an investigation found significant violations of the Fair Labor Standards Act, including improper payment of overtime. Wage and Hour administrator David Weil said Tuesday in a news release that changes in the oil and gas industry have made it ripe for noncompliance.