Youths at the Shuman Detention Center have attacked staff members five times since Jan. 1, stabbing a nurse with a pen once and, in another instance, kicking a youth care worker in the head so hard he suffered a concussion.

In December, a worker trying to disarm a teen who had a sharp piece of sheet metal was punched in the face several times, and now faces surgery for an injured shoulder.

Some worry these incidents reflect an increasingly dangerous work setting for the Shuman staff, but Director William T. "Jack" Simmons said the assaults do not signal an unusual increase in violence by teens at the center.

"This is detention. We have incidents all the time between residents and staff. That's not newsworthy."

Five incidents in two months is not surprising for a center the size of Shuman, agreed Ann Marie Ambrose, director of Child Welfare and Juvenile Justice Services for the state. "This really wasn't on our radar screen as a big issue."

But Ms. Ambrose said she was not aware of the concussion which, combined with the pen stabbing and the worker injured in December, cast the recent incidents in a new light.

"Now I want to go back and look a little bit deeper."

Although early in the year, the current rate of assaults puts Shuman on a pace similar to the 105-bed Youth Study Center in Philadelphia, which reported 37 assaults on staff members in 2007, none requiring hospitalization. State officials say Shuman, with 130 beds, reported only one assault on staff in 2007, although a statewide transition to a new incident reporting system may have skewed the tally.

Detention center directors in neighboring Beaver and Westmoreland counties, which house only about 25 adolescents each, said attacks on staff are extremely rare for them.

"It's been numerous years," said Robert Rose, director at Allencrest in Beaver County.

Peter Chapman, director of Westmoreland County Regional Youth Center, believes no staff member there has been assaulted in at least 10 years.

Other parts of the state, though, have seen disturbing outbreaks of violence.

Two weeks ago, 10 youths at the Cornell Abraxas I residential program in Marienville, Forest County, attacked other residents and staff, resulting in injuries to eight staff members. State police responded and several teens have been charged with riot and aggravated assault.

The week before that, three adult teens were sentenced to five to 15 years in state prison for their role in a December 2006 riot at the North Central Secure Treatment Unit in Danville, Montour County. Four other juveniles, including two from Allegheny County, also were adjudicated after inflicting serious injuries on several staff members.

"Three of the staff members are still partially or completely disabled, after 15 months. One fellow just had back surgery," said Montour County District Attorney Robert Buehner Jr., who prosecuted the cases.

At one point, he said, staff members tried to lock themselves in a room until police arrived. One of the teens broke a window with a fire extinguisher to get at them.

Ms. Ambrose said she does not believe teens in detention are getting more violent. With both the Cornell Abraxas and North Central Secure incidents, she said, specific problems could be found in programming or staffing.

"At Danville, there were a million contributing factors," she said. As for the Cornell Abraxas program, "I'm a little concerned that they didn't see there were troubling signs" before the teens rioted. That program has temporarily stopped admitting new teens.

Jim Rieland, director of Allegheny County Probation, said he's seen other evidence of increasing attacks on authority figures by young people -- last year, 245 reports of assaults against teachers in Allegheny County were referred to the probation office, compared with 102 in 2002.

"These are not just in city schools either, as some people might think. They are from all parts of the county," Mr. Rieland said. "When you have in the school environment a student who is willing to put their hands on a teacher, it signifies to me a complete breakdown of social control."

If the trend toward greater violence is real, it can take on particular urgency in a setting such as Shuman, which has been operating at or above its capacity much of the past year. Overcrowding also has been an issue in other detention centers across the state, said Nicole Remsburg, executive director of the Juvenile Detention Centers Association of Pennsylvania.

Adolescents are brought to Shuman to await a hearing for offenses ranging from retail theft and simple assault to murder, unless the case is referred to adult court. Mr. Simmons, who became director of the Lincoln-Lemington facility June 1, said adolescents typically stay 15 to 18 days. But some stay several weeks, even months, if a placement cannot be found.

Finding placements has been an ongoing issue, particularly for teens with a history of aggression, and especially if they also have mental health problems. Many believe those extended stays add to the tensions within the facilities.

Yet the possibility that the state will force private residential programs to accept, and keep, the most troubled teens has made those programs more cautious.

"Over the last four to five years, I would bet that 70 percent have tightened admission criteria," said Bernadette Bianchi, executive director of the Pennsylvania Council of Children, Youth and Family Services, a statewide association of those private agencies.

That, in turn, means the teens with a history of aggression and violence stay in detention longer, exacerbating the overcrowding problems there.

The frontline workers who deal with violent adolescents also are facing pressure from the state not to use physical force. Department of Public Welfare officials have made it clear that they want programs to reduce or eliminate the use of physical restraints.

"The goal every day is to not have any restraints," said Ms. Ambrose, though she acknowledged that can be difficult when working with violent and unpredictable teens. Workers certainly are allowed to defend themselves, she said. "We really try to support the folks doing this work, but we also know there are proven methods of dealing with kids that are effective" without using restraints.

Use of restraints is controversial, and calls to eliminate their use surface whenever a young person is seriously hurt or killed. In January 2007, for example, 17-year-old Isaiah Simmons, of Baltimore, died at the Bowling Brook Preparatory School in Maryland -- where Allegheny County had sent adjudicated youth in the past -- after counselors held him face down for close to three hours.

But program providers say limiting use of restraints poses risks, too, if they can't calm the teens by talking to them.

Workers also worry about being accused of abuse if a thrashing child gets injured.

Ms. Ambrose said they take into consideration whether an injury is accidental. The agency had found abuse occurred when workers beat a child in their care, or threw a phone at a teen, she said.

But, in one instance, the agency determined a worker abused a resident after an improperly applied physical restraint resulted in a teen's broken elbow.

Staff members "are second-guessing themselves about when to intervene. They're more reluctant," said Ms. Remsburg. "What message is that delivering to the kids?"

Mr. Rieland said teens will notice if staff become hesitant to intervene, and likely will be more emboldened to strike out at other residents or staff if they think they can get away with it.

"My fear is that you could end up with more kids being certified to criminal court," he said. "One of the things I hope is not done is that we lose more kids to prison."