Washington State Insurance Commissioner Mike Kreidler is fining four insurance companies a total of $100,000 after they overcharged thousands of consumers across the state.

The companies are Hartford Accident and Indemnity Co., Hartford Casualty Insurance Co., Hartford Insurance Co. of the Midwest and Trumbull Insurance Co.

They have agreed to pay the fine and to refund more than $1 million in overcharges to consumers, including 8 percent interest.

The overcharges affected nearly 4,800 auto policies between 2009 and 2013. The affected consumers were notified by the companies and refunds sent out in April.

“To their credit—and as required by law—the companies self-reported the error that led to these overcharges,” Kreidler said, in a news release. “They also promptly agreed to issue the refunds.”

The companies have notified the consumers who were overcharged. The error stemmed from the companies using an unapproved rating factor when calculating premiums on policies in which consumers’ previous insurer was a non-standard insurer.