A York County teenager was arrested on felony assault charges after he allegedly punched and headed butted an employee in a weekend altercation at a juvenile detention and treatment facility in northern Butler County, authorities said.

Jorge L. Mercado, 17, of York also is accused of threatening to kill staff members during the incident Sunday afternoon at the Western PA Child Care on Route 38 in Allegheny Township.

He is being held in the Butler County Prison in lieu of $50,000 bond.

State police said Mercado got into a fracas with several staff members about 12:45 p.m. He is suspected of picking up a chair and threatening to “end people” by hitting employees over the head with it.

Staffers moved in and tried to restrain the teen, police said. But the boy broke free and twice punched one of the staff members, a supervisor. He also allegedly headed-butted the same employee.

Authorities said there is surveillance video of the incident.

The injured worker suffered a small bruise on his left cheek, police said, and he complained of a headache. Medical staff at the facility tended to him.

District Judge Lewis Stoughton arraigned Mercado on three felony counts of aggravated assault, a misdemeanor charge of terroristic threats and a summary charge of harassment.

Mid-Atlantic Youth Services operates PA Child Care, a facility that houses both secured and nonsecured units for males and females from ages 16 to 21 who have been placed there following court disposition of their juvenile cases.

Greg Zappala, facility president, declined comment Monday.