CHICAGO (WLS) -- As Illinois state lawmakers consider legalizing recreational marijuana, Illinois state Treasurer Mike Frerichs has proposed a new banking law to prohibit regulators from punishing banks that serve the legal cannabis industry.Legal marijuana sales in Illinois last year totaled over over $136 million - and it was all sold in cash. State and federal rules prohibit banks and credit unions from doing business with the cannabis industry."Running an all-cash business is definitely a safety concern. It's an inconvenience for patients picking up their medicine, we are supportive of any legislation that will open up banks and give us the ability to accept credit cards like every other business has," said Jason Erkes, spokesman for CRESCOlabs.It's not just an inconvenience for the customers, but CRESCOlabs and other Illinois medical marijuana companies say without access to banks, paying bills and employees, getting a loan or even checking account are all challenges with a cash-based business."If we don't make these changes and we do not bring our rules and regulations in line with our laws, we invite crime, theft and tax evasion," said Frerichs.Frerichs is pushing legislation that would prohibit state regulators from penalizing banks and credit unions for serving cannabis-related businesses. But, state action is not enough since marijuana remains illegal on a national level."I'm working with treasurers from other states - both Democrats and Republicans - to encourage federal regulators for not punishing banks the serve the legal cannabis industry," said Frerichs.With over 30 states with some form of legalized marijuana, state treasurers are hoping to put pressure on Congress to bring outdated banking laws into the present, especially since the cannabis industry is only growing.