Congress voted to continue a long-standing 50-cent-per-gallon tax credit for those who dispense natural gas for vehicles. As a result, Questar Gas has applied the credit to its 2010 investment to improve CNG stations. Beginning Dec. 23, however, the company split the credit – half is used to reduce the price of natural gas at the pump by 25 cents per gallon, and the other half will be designated for CNG-station improvements.