Senate debate on a bill to make it harder for workers to sue for discrimination in Missouri went on for hours late into Tuesday night as Democrats slammed the proposal as a way to remove punishments for intolerance in the workplace.

At issue is a measure that would require plaintiffs bringing such lawsuits to prove that race, religion, sex or other protected status was the sole reason for discrimination or being fired, rather than just a contributing factor. It also would prevent employees from suing other workers and cap damages in discrimination lawsuits.

State agencies, including public colleges and universities, no longer would face punitive damages in such lawsuits under the latest proposal.

Republican lawmakers and pro-business groups such as the Missouri Chamber of Commerce and Industry it's too easy to sue for discrimination in the state. But Democrats, trial attorneys and advocacy groups such as the NAACP are slamming the proposed change as a way to allow discrimination without legal consequences.

Black lawmakers and others say its passage would undo progress made to end racial segregation and other discriminatory policies. Missouri NAACP President Rod Chapel told reporters hours before senators debated the bill Tuesday that the measure was "hyped-up Jim Crow," and black Kansas City Democratic Sen. Kiki Curls called it "embarrassing."

"We're wanting to go back to 1961," Curls said, referencing when lawmakers adopted the Missouri Human Rights Act. "That is so offensive and hurtful and degrading to every black person in this state."

Sen. Gary Romine, a Farmington Republican who is sponsoring that chamber's version, said past court rulings moved Missouri away from federal standards for discrimination lawsuits and the original Missouri Human Rights Act. On Monday, he said the current standard requires a minimal burden of proof and "holds an employer liable for actions that would have occurred without the impermissible act."

He told colleagues on the Senate floor Tuesday that a higher standard is needed to appropriately deal with "actual discrimination."

An employment discrimination lawsuit filed against Romine's rent-to-own furniture business is pending. When asked by a Democratic colleague on the Senate floor Monday whether sponsoring the measure is a conflict of interest, Romine said he previously proposed changing state discrimination lawsuit policies — in December 2014, roughly four months before his business was sued.

The measure under consideration in the Senate is similar to a House bill that Chapel briefly spoke against in a public hearing in mid-February before the committee chairman interrupted him and called on someone else to speak. Chapel called that discrimination, and Republican Rep. Bill Lant, of Pineville, later said he would hold another hearing to allow him to continue speaking. That has not yet been scheduled.

A proposal by Creve Coeur Democratic Sen. Jill Schupp to amend the Senate measure to add gender identity and sexual orientation to classes protected under the Missouri Human Rights Act also has not yet come to a vote.

Around midnight, lawmakers chatted about baseball on the Senate floor as colleagues tried to hammer out a deal.