"In the same time frame" the donations occurred. Walked signed into law changes passed by the Republican-led Legislature that would have made companies like NL Industries effectively immune from compensation claims for lead paint poisoning.

According to one document cited in the report, a lobbyist for NL Industries suggested to Senate Majority Leader Scott Fitzgerald, R-Juneau, which language should be used to make the effective immunity retroactive. The phrase suggested by the lobbyist is the one that was added to an amendment, which was passed and signed into law but later blocked by a federal court.

A spokeswoman for Fitzgerald did not immediately return a request for comment.

Federal courts have since overturned most of the changes outlined in the Wisconsin law.

"But the point remains: had the new provisions been allowed to stand, they had the potential to save the company and others like it millions of dollars in damages," the report reads.

The Guardian U.S. report notes there is no evidence Republican legislators tried to change those laws as a direct result of Simmons' donations to the group that supported some of them in their recall elections. But it closes with questions about the appearance of quid pro quo resulting from that relationship.