OLYMPIA, Wash. — A judge has affirmed Washington state’s procedures for executing prisoners by lethal injection, turning aside complaints that condemned inmates could be partially conscious when fatal drugs flow into their veins.

In a ruling released today, Thurston County Superior Court Judge Chris Wickham said that the inmates presented no evidence that the state “intended to impose punishment that was ‘cruel.”’

“The procedure to be used by defendants, although not fail-safe, appears to have been designed to administer the death penalty in a way that is humane for the inmate and the observers,” Wickham wrote. “It is an attempt to provide some dignity to this most grave event.”

The inmates are likely to appeal the ruling. A message left with one inmate’s attorney this morning was not immediately returned.

The lawsuit, filed by three death-row inmates, argued that Washington’s preferred method of execution needs a major overhaul to satisfy constitutional bans on cruel punishment.

The lawsuit did not seek to end the death penalty in Washington. Instead, the inmates’ lawyers asked the state to trade its current mix of three intravenous drugs for a large dose of one powerful sedative — an approach that plaintiffs said would kill a condemned prisoner with virtually no risk of pain or suffering.

Attorneys for the state countered that Washington’s lethal injection system passes constitutional tests because it is substantially similar to a Kentucky system upheld last year by the U.S. Supreme Court.

Washington, like roughly three dozen states, performs lethal injections by administering successive doses of three separate drugs. The chemicals are intended to render a condemned prisoner unconscious, then paralyze the person’s body, and, finally, stop the inmate’s heart.

The lawsuit, however, argued that Washington’s lethal injection procedures are so sloppy and inconsistent that inmates might be partially conscious when fatal drugs flow into their veins. If that happened, the condemned person could be subjected to suffocation and excruciating pain.

The lawsuit alleged a long list of shortcomings in the state’s lethal injection methods: No supervision by doctors or nurses, inadequate training and rehearsals for the execution team, and lack of medical qualifications for everyone involved.

At trial, lawyers for the state said the lawsuit essentially demanded “a perfect execution.” But the state said prison officials were not required to prove that execution procedures would be followed in a flawless manner that eliminated all risk of pain.

Moreover, the similarities between Washington’s policies and those of Kentucky — including the requirement of some medical training or experience for the execution team — are strong enough to prevent a substantial, intolerable risk of harm, the state said.

The state also rejected the plaintiffs’ argument that the Washington Constitution offers a stronger protection against cruel punishment than the U.S. Constitution’s Eighth Amendment.

The case is a combined lawsuit on behalf of three death row inmates: Darold Stenson, who shot his wife and business partner in Clallam County; Cal Coburn Brown, who tortured and killed a Burien woman; and Jonathan Gentry, who killed a 12-year-old girl in Kitsap County.

Washington death row inmates may opt for hanging instead of lethal injection. The state’s last execution was the lethal injection death of James Elledge in 2001.