Victims with fake injuries and bandages? Hospital staff dressed in full haz-mat gear? No, this is not just another Halloween event at Holy Cross Hospital.

Rather, the Silver Spring-based hospital is participating in a mock exercise today with other Montgomery County hospitals, the county’s Office of Emergency Management and Homeland Security announced.

The exercise will test how well the regional hospitals respond and work together in a crisis situation such as a terrorist attack or a natural disaster that leaves mass casualties in its wake.

“As the scenarios come in, we just respond to them,” said Yolanda Gaskins, a spokesperson for Holy Cross Hospital. “We don’t know what the scenarios will be.”

Gaskins warned that area residents should expect unusual helicopter traffic since “patients” will be transported to various hospitals as required by the emergency scenario.

The drill will not affect normal hospital procedures, Gaskins said, so real patients should not face a longer wait in emergency rooms.