The protracted execution of Stephen Peter Morin in Texas yesterday morning, during which technicians took nearly 45 minutes to find a vein that would carry the lethal injection, approached cruel and unusual punishment, a lawyer for the American Civil Liberties Union charged.

But corrections officials noted that Morin, whose veins had deteriorated from years of drug use, raised no objections.

"He told the technicians he'd often had the same problem when he was trying to give himself a fix," corrections department spokesman Phil Guthrie said. He described Morin, a convicted killer, as "calm and cooperative" while he lay strapped on the gurney as medics probed his limbs for a usable vein.

Texas Attorney General Jim Mattox said afterward: "I've witnessed several of these executions and I would say, despite the time it took to find the vein, this was the least violent of any."

"The length of time it took for the state to kill him shows that resorting to the needle is no more humane than any of the other methods," said Jim Harrington, legal director of the Texas ACLU. The organization opposes capital punishment.

Morin, convicted of killing three young women within five weeks in 1981, had rejected attempts to delay his execution. An estimated 10 other inmates on the state's death row at Huntsville reportedly are seeking quick executions and have sent letters to the courts saying so.

Death-row inmate Charlie Bass, whose cell was next to Morin's, described Morin to an Associated Press reporter as "jolly and looking forward to it."

A drifter from Providence, R.I., Morin, 37, was executed for shooting to death a 21-year-old San Antonio woman, Carrie Marie Scott, in 1981. He pleaded guilty to capital murder in that case, the second person in Texas history to enter such a plea. He faced death sentences in two other killings, in Texas and Colorado; had been linked to other slayings and had a lengthy arrest record from coast to coast.

Texas corrections officials said that they will continue to use the injection method. If another drug user comes to the death chamber, "we'll probably have the same problem," Guthrie said.

Prisoners are strapped and immobilized as they wait on the gurney, he noted, in case they panic or try to resist.

Supporters of execution by lethal injection defend it as the most humane procedure, but critics denounce it as sugarcoating a morally reprehensible act.

Henry Schwarzschild, director of the capital punishment project of the ACLU, called the procedure as "stomach-turning and barbaric" as any form of state execution but said there is probably no feasible legal challenge to be made. He noted that the courts have accepted other delays in execution logistics, such as power failures in electric chairs.