CHICAGO (CBS) — A new drive-through coronavirus testing site for Chicago area first responders was forced to start turning people away after less than four hours on Monday, as swarms of people flocked to get checked out for COVID-19.

The Illinois Department of Public Health opened a drive-up testing facility in the Dunning neighborhood, at the site of an old vehicle emissions testing facility at 6959 Forest Preserve Drive.

Starting at 9 a.m. Monday, first responders were allowed to line up to get tested for the novel coronavirus. By 12:45 p.m., the site already had reached its daily limit of 250 tests, according to the Chicago Fire Department.

The Fire Department said no more vehicles would be allowed to get in line. A new line will be allowed to begin at 9 a.m. Tuesday.

Fire Department employees must be off duty to line up for the tests, and must bring proper identification. Retired firefighters, and relatives of active firefighters are not allowed to get tested at the site.

Illinois public health officials have been working with the federal government, Walgreens, and Wal-Mart to set up drive-through testing sites in the areas hit hardest by COVID-19. Those sites will focus on administering tests to those who need them most — seniors, first responders, and healthcare workers.

The drive-through sites are designed to help front-line workers in the fight against COVID-19 get tested for the virus, while limiting its spread to others.