A bill that requires Maine hospitals and other health care facilities to clearly inform patients that they charge facility fees automatically became law Thursday after Gov. Janet Mills declined to sign it or veto it.

Health care facilities must post signs in their buildings and on their websites that facility fees are being charged – though hospitals and other facilities do not have to disclose the specific amounts of the fees.

The law is a weakened version of the original legislation for L.D. 2271. Some provisions were taken out amid opposition from the medical industry that the bill would have negative financial impact on hospitals’ ability to cover their overhead. That includes a proposed full ban on the facility fees charged at health care facilities that are affiliated with a hospital but separate from the main campus.

Lawmakers also removed a provision that would have barred fees for telehealth patients who do not visit a health care facility.

The legislation that became law Thursday followed a Press Herald investigation into Maine’s medical-billing system that in part revealed confusing medical bills sometimes carry arbitrary and hidden costs, including facility fees that often ran into hundreds of dollars just for receiving treatment in a hospital and that insurance companies often refused to cover.

Mills was expected to approve the bill or let it take effect without her signature. After 10 days passed without Mills taking action, a bill not signed or vetoed automatically becomes law. Mills had not taken a public stance.

The law will go into effect in 90 days.