When an airhorn sounded at Dutch Wonderland on Thursday, the controlled chaos began.

More than 70 students volunteers ran screaming from the park’s diving arena as a simulated chlorine gas leak spewed smoke into the air. Another 30 students stayed behind, pretending they were among the injured.

As firefighters rushed to the scene, one fell in mock distress after being overwhelmed by the fumes. Then the popping of firecrackers could be heard, simulating gunfire and yet another emergency.

Before long,word leaked to the press that the “shooters” had taken “hostages.”

Between 300-400 people participated in the full-scale mass casualty exercise, organized by the Lancaster County Counterterrorism Task Force and held at the Lincoln Highway amusement park.

Duane Hagelgans, battalion chief for the Lancaster City Fire Department, said community groups, churches, county government employees and local emergency responders all combined to make more than four years planning a successful reality.

“We started planning this back in early 1999,” Hagelgans said. “We’ve been meeting about it every month since and, for the last four months, every other week.”

Ambulance companies from all over the county, as well as the city’s firefighters, police patrol officers, bicycle patrol officers, were among the drill’s first responders.

State Police and police from East Lampeter Township and West Lampeter Township also got in on the act. The Lancaster County hazardous materials teams and at least six area fire departments were part of the drill which included, Bird In Hand Fire Company, Eden Fire Company, Ronks Fire Company, Witmer Fire Company, Strasburg Fire Company, Lafayette Fire Company, Hagelgans said.

More than 150 students from Lancaster Mennonite High School, Lampeter Strasburg High School and Conestoga Valley High School portrayed victims.

Local politicians also were on hand for the event. Retiring county commissioner Paul Thibault and incumbent County Commissioner Pete Shaub watched from a distance as medical crews worked to retrieve victims and CERT teams worked to rescue “hostages.” In his bid for county commissioner, recorder of deeds Steve Mcdonald used the event as an opportunity to introduce the Lancaster County “First Responders’ Initiative.”

“The men and women engaged in the disaster drill that is happening now deserve the support of the community,” Mcdonald said. “We’ll watch our friends and family put lives at risk to protect us: it’s time we do something for them.”

The initiative calls for a local “Homeland Security Fund” made up of charitable tax-deductible donations from local businesses and residents.

“Firefighters, police and ambulance crews are here today as part of an effort to get us ready, but they can’t do it alone,” Mcdonald said. “they need equipment and training, and we can’t depend on the federal to buy it all.”

Hagelgans said the local counterterrorism task force has existed since 1997, well before the terrorist attack on Sept. 11,2001.

“We never really talked much about it before because we didn’t want to scare people,” Hagelgans said. “But our task force is really part of the South Central Pennsylvania Counter-Terrorism Task Force, which is all organized by PEMA ( Pennsylvania Emergency Management Agency).”