A supplier of Texas’ execution drugs can remain secret under a court ruling Friday that upheld risks of “physical harm” to the pharmacy, ending what state officials called a threat to the entire U.S. death penalty system.

The decision by the Texas Supreme Court, where Republicans hold every seat on the bench, doesn’t change operations at the nation’s busiest death chamber because state lawmakers banned the disclosure of drug suppliers for executions starting in 2015.

A lawsuit filed a year earlier by condemned Texas inmates argued that the supplier’s identity was needed to verify the quality of the drugs and spare them from unconstitutional pain and suffering. Lower courts went on to reject Texas’ claims that releasing the name would physically endanger pharmacy employees at the hands of death-penalty opponents.

Now, however, the state’s highest court has found the risks valid and ordered the identity of the supplier to stay under wraps.

“The voters of Texas have expressed their judgment that the death penalty is necessary, and this decision preserves Texas’ ability to carry out executions mandated by state law,” Republican Texas Attorney General Ken Paxton said in a statement.

The court deciding that a “substantial” risk of harm exists appeared to largely hinge on an email sent to an Oklahoma pharmacy in which the sender suggested they enhance security and referenced the bombing of an Oklahoma City federal building in 1995.

“I’m speechless with the absurdity of them relying on that singular fact to close, to keep in secret how Texas essentially carries out its execution,” said Maurie Levin, a defense attorney who helped bring the original lawsuit.

The availability of execution drugs has become an issue in many death penalty states after traditional pharmaceutical makers refused to sell their products to prison agencies for execution use. Similar lawsuits about drug provider identities have been argued in other capital punishment states.