CHICAGO (CBS) — State officials were warning people planning to watch Monday’s total solar eclipse to be careful about where they buy their safety glasses.

According to the Illinois Attorney General’s office, fake eclipse glasses have flooded the market, and using them could result in eye damage.

It’s especially important to wear protective eyewear or use a pinhole projector to view any eclipse, but especially a total eclipse like the one on Monday.

Downstate Illinois lies along the path of totality for the eclipse, so towns like Carbondale, Makanda, Marion, and Makanda are expecting large groups of tourists to watch the moon completely block out the sun for more than two minutes Monday afternoon.

The attorney general’s office suggested viewers visit the American Astronomical Society for a list of solar filters and viewers that meet safety standards to watch the eclipse.

The federal government has warned people to only use new devices. If they are more than three years old, they won’t properly protect your eyes.

The Adler Planetarium was giving away free eclipse glasses Thursday afternoon in Grant Park, starting at 2 p.m. at the corner of Roosevelt and Indiana. The planetarium also was giving away glasses Friday at Lagunitas Brewing Company at 12:30 p.m.