(NEXSTAR) – A Costco in New Jersey was evacuated on Wednesday morning after a refrigerant leak inside the store sickened about 20 people, according to police.

Costco staff contacted police in Hazlet Township with reports of the leak (which police described as a “Freon leak”) at approximately 6:45 a.m. before attempting to ventilate the building and delay its opening, the Hazlet Township Police Department wrote on Facebook. At around 9:30 a.m., the store called back to report approximately 20 people experiencing nausea and headaches.

The store had been evacuated by the time emergency personnel arrived. The Monmouth County EMS Task Force also provided somewhere between 15 and 20 ambulances, according to the Facebook post.

Five of the sickened individuals were ultimately sent to nearby hospital for treatment, a representative for the Hazlet Township Police confirmed to Nexstar.

The Costco location remained closed on Wednesday. A representative for the location confirmed the store had reopened for normal operating hours on Thursday.

Refrigerants, such as Freon, can be dangerous if inhaled, or if they make contact with the skin or eyes in liquid form, according to the CDC’s National Institute for Occupational Safety and Health. Exposure may cause dizziness, tremors, asphyxia, unconsciousness or even cardiac arrhythmias or arrest. Exposure to liquid forms may also cause frostbite.

Hazlet’s Office of Emergency Management was contacted for additional information concerning the specific type of refrigerant involved in Wednesday’s leak, and the status of those sickened.