FLORENCE - A judge yesterday ordered a former Arizona Boys Ranch nurse to face manslaughter and child abuse charges in the death of 16-year-old Nicholaus Contreraz.

Judge Richard Fields of Pima County Superior Court ruled that two other former Boys Ranch workers will face child abuse charges, while he cleared two others of all criminal wrongdoing.

The judge dismissed murder charges against all five ex-workers in Contreraz's March 2, 1998, death at the privately run paramilitary camp for troubled youths.

Nurse Linda Babb, 45, charged with manslaughter and reckless child abuse, treated Contreraz several times without diagnosing his lung infection.

By the time Contreraz collapsed and died, that infection had filled his chest with more than 2.5 quarts of pus and had collapsed a lung.

Authorities said the other four workers either watched or forced Contreraz to exercise before his collapse. Troy Michael Jones, 27, and Montgomery Clayton Hoover, 30, will face child abuse charges.

However, Geoffrey Sean Lewis, 24, and Michael Martin Moreno, 31, walked out of the courtroom free of any criminal allegations.

Attorneys representing the three former workers still facing charges will try to persuade Fields to reconsider his decisions in a telephone conference tomorrow morning.

``This is a tragic case for everyone involved,'' said Fields, who spent two weeks reviewing four days of testimony and more than 2,000 pages of investigative reports and court documents. He had cautioned the packed courtroom against outbursts before stating his detailed findings.

Julie Vega, Contreraz's mother, sobbed when Fields cleared all five of murder, but said outside the courtroom that she believed the judge's decisions were fair.

Embracing her son Mark and a sister, Vega said she placed much of the blame for Nicholaus' death on Babb, the nurse. ``It was obvious she hadn't done her job,'' she said. ``I could tell my son didn't die easily.''

The teen-ager's family traveled to Florence for court proceedings from its home in Sacramento.

Boys Ranch runs camps mainly for troubled youths referred by courts. The youth's death prompted an investigation that ultimately led to the closure of its camp near Oracle.

Prosecutors maintain that the teen's illness developed for at least a week before his death, and that other boys at the boot-camp-style facility north of Oracle noticed he had symptoms as vomiting, diarrhea, coughing, weight loss and difficulty breathing with any exertion.

Deputy Pinal County Attorney Janna L. Vanderpool described how the boy died of oxygen deprivation - ``a noisy, obvious, gruesome, extended death'' - after he was carried to a secluded amphitheater and made to exercise at dinnertime.

Babb had several contacts with Contreraz in the days before his death, and allowed him to take part in heavy exercise despite knowing he had breathing problems, Vanderpool alleged. She noted that the nurse also documented a number of bruises on the teen the day before his death but failed to report or question them.

``She obviously wanted to keep her job more than she wanted to protect Nicholaus,'' Vanderpool said yesterday in her closing argument. She suggested that Babb either didn't care about the boy or was intimidated by other workers.

Babb's attorney, Stephen M. Weiss, however, described his client as a woman who went beyond her job description to care for the boy.

Outside the courtroom he said his client was ``really upset'' at the judge's decision. Although she had prepared for the worst, he said it was still a shock.

The attorneys of the four other workers had maintained during the preliminary hearing that their clients had no reason to suspect the boy was gravely ill after the nurse examined him.

``The bottom line is she had the most contact with him of the whole group,'' Weiss said. He said he would consider asking that Babb, who now works with computers in Phoenix, be tried separately.

The closing arguments presented by the other defense attorneys noted that Contreraz appeared defiant rather than pleading to them for help, and could have been inducing hyperventilation by taking short breaths.

``All that Mr. Hoover knew was he was dealing with a young man who had a history of malingering,'' said Hoover's attorney, Edward F. Novak.

Michael Bloom, who represented Moreno, stressed outside the courtroom that it was important to remember that the findings do not convict the other three people. He also criticized the prosecutor for what he said were numerous misstatements.

Although Moreno was relieved, Bloom said, ``this has been devastating to Michael - to have his name dragged through the mud.''

Vega said she agreed there was no reason for Moreno, a supervisor who had little contact with the boy, ``to go through this any further.''

The Pinal County Attorney's Office originally indicted each of the five former employees in September on child abuse and manslaughter charges. The charges were dropped after defense attorneys alleged that errors occurred when prosecutors presented the case to the grand jury.

Prosecutors then refiled a criminal complaint in March, but with the possibility that the workers could face first-degree murder charges.

The five workers were among 17 accused of child abuse or neglect and cited on administrative charges by Child Protective Services officials after a five-month investigation of Boys Ranch last year.

Yesterday's dismissal of criminal charges against Moreno and Lewis means they can now appeal the CPS charges against them to avoid having their names placed on a state registry of child abusers, said an official who oversees CPS.

``We stand by our original decision, based on the facts, to bring child abuse charges against (all five of) them,'' said Jim Hart, assistant director of the state Department of Economic Security's Children, Youth and Families Administration.

Prosecutors face a higher burden of proof in a criminal case than CPS does in an administrative case.

Only one of the 17 accepted being registered as a child abuser without appealing. Charges against 11 others are under appeal.

CPS investigators found ``a pattern of abuse and neglect and a lack of concern'' for the rights of boys that led to the death of Contreraz, DES Director Linda Blessing said last August. Contreraz at times was ridiculed and forced to carry a bucket containing clothes soiled with his vomit and excrement.

State officials have refused since last August to renew the ranch's operating license. Hart said yesterday that the state has nearly finished negotiating terms under which the ranch, which has continued operating, would get back its license and stay open under the eye of a consultant who recommended reforms.

The state has also settled a $3 million claim filed last summer by Contreraz's mother, who accused DES of failing to competently oversee Boys Ranch even though there had been documented cases of abuse before her son died. Hart said he did not know the settlement terms.

Arizona Daily Star reporters Enric Volante and Rhonda Bodfield Sander contributed to this story.