Falls police Lt. Hank Ward warned Levittown residents not to be alarmed if they see SWAT teams on area roads Saturday.
Police from around the county and Philadelphia will be taking part in a massive emergency drill at the Air Liquide facility on West Steel Road at around noon.
The drill, which is expected to last for 4 hours, will prepare local SWAT operators to deal with an active shooter in a chemical facility.
Over 70 emergency personnel will be involved in the event that will include crowd control and simulated weapon fire, Ward said.
The drill will be overseen by the Department of Homeland Security and will use assets obtained by the Philadelphia Joint Terrorism Task Force.