CHICAGO (CBS) — They are pop-up sites that only serve those who are on the front lines fighting COVID-19.

CBS 2’s Steven Graves reports, if Monday was any proof, the need for more testing is very much needed.

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A parking lot usually filled with shoppers is now being used in the fight against a global pandemic. The COVID-19 drive-thru testing site at a Joliet Walmart closed in an hour.

A sign read “no more testing.”

For those who made the line, the wait lasted a while. After that wait, a nasal swab test was administered by a U.S. D Department of Health and Human Services worker or a pharmacist.

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It’s one of two Walmart stores in the Chicago area, the other in Northlake, that is just treating first responders and healthcare workers who feel symptomatic or feel they’ve been exposed.

Each location can give up to 150 tests. Operations like these are critical among a lack of coronavirus tests nationwide. It’s prompted other big businesses to open sites in the area, like a Walgreens in Bolingbrook.

The company’s pilot operation only offered to first responders and medical staff. No one allowed inside the facility. Patients must stay in the vehicle and have identification.

For the time being, all sites in the area remain closed to the general public.

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Both companies are working out details on additional days and locations. Stores like CVS and Target have announced similar coronavirus testing efforts.