SPRINGFIELD, Ill. (AP) — Illinois medical marijuana companies may have to deal in cash after the main bank serving operators has decided to pull out of the industry.

The Chicago Tribune reports that the Bank of Springfield informed cannabis clients last month it would close their accounts May 21.

The decision to withdraw is tied to the January reversal of a policy from President Barack Obama’s administration that discouraged prosecuting operators under state marijuana laws.

Banks are hesitant to get involved in the industry because marijuana remains illegal at the federal level. Many medical marijuana companies now face not having the bank accounts they use to pay their employees, vendors and the government.

The state Department of Public Health says the industry had $8.5 million in retail sales in February.