A 10th station refused to settle and is fighting the allegations in Greene County, Mo. Missouri Attorney General Jay Nixon sued the gas stations under a relatively obscure state law protecting consumers from unwarranted price hikes.
Pump prices jumped well beyond $3 per gallon after the hurricane Aug. 29. Nixon said one gas station in Springfield, Mo., boosted its profit margin 400 percent immediately after Katrina hit.
"Three dollars per gallon is absurd," Nixon told the St. Louis Post-Dispatch.
Nixon's office received more than 350 complaints of gas price gouging. Fines go to local school districts.
The executive director of the Missouri Petroleum Marketers and Convenience Store Association said price gouging in Missouri was not an industry-wide problem.
Illinois Attorney General Lisa Madigan is investigating hundreds of similar complaints.
Notable deaths of 2014 [PHOTOS]