Exhibit No. 12. Questar Gas Company Ratio of Earnings to Fixed Charges 12 Months Ended March 31, 1997 1998 (Dollars in Thousands) Earnings Income before income taxes $48,603 $39,920 Plus debt expense 16,707 19,903 Plus allowance for borrowed funds used during construction 265 317 Plus interest portion of rental expense 170 306 $65,745 $60,446 Fixed Charges Debt expense $16,707 $19,903 Plus allowance for borrowed funds used during construction 265 317 Plus interest portion of rental expense 170 306 $17,142 $20,526 Ratio of Earnings to Fixed Charges 3.84 2.94