Republican lawmakers in Ohio are moving to make details of executions committed by the state secret from the public.
Republicans are trying to force through the bill before the state's next scheduled execution on 11 February.
It would prevent details of the execution, including the drugs used for the lethal injection, the source of the drugs, and the identity of medical experts involved in the execution being released from the public.
Courts and the legal representatives of death row inmates would also be barred from accessing the information under the bill.
"This bill is trying to do an end run around the courts. When things aren't going well, the state is making its actions secret because they don't want people to see them screwing up," Mike Brickner, senior policy director of the American Civil Liberties Union (ACLU) in Ohio, told the Guardian.
The legislation, framed by Republican state lawmakers Jim Buchy and Matt Huffman, has been passed by the state House of Representatives and will now go before the state's senate.
State Republican leaders want it passed by 17 December, with a federal moratorium on executions in the state, imposed for Ohio to review its execution procedure, due to expire in the new year.
The move comes after a series of botched executions in the state.
In January, Dennis McGuire was injected with an experimental combination of drugs. Witnesses said that it took him 26 minutes to die, and that he struggled and gasped for breath.
A number of other high-profile botched executions have provoked debate over whether lethal injections using untested chemicals ought to be banned.
US states which carry the death penalty have struggled to source drugs for legal injections, after pharmaceuticals firms in European refused to sell them deadly chemicals following a 2011 ban on sales by the European Commission.
The bill provides means to override the boycott, by declaring void any contract that prohibits the distribution of drugs to the Ohio department of corrections, opening the way for drugs to be purchased secretly.
Brickner told the paper that he expects the secrecy bill to be challenged.
"It's very unclear whether such secrecy would be upheld in a court of law. Our courts don't look kindly on measures that stop them doing their jobs properly," he said.