CHICAGO -- It's not your imagination if you've walked outside and noticed a rusty colored dust sprinkled all over your car.

The strange rusty powder appeared on cars in the Chicago area this week.

Angelo Mavaraganes, who runs a car repair shop on the Northwest Side, said he has seen it on at least 30 cars the last few days.

"One came from Crystal Lake, and one was from Mount Prospect, and another one from Homewood/Flossmor," Mavaraganes said.

The Illinois Environmental Protection Agency sent a field agent to collect evidence of the powder.

"He and myself together, we collected a sample," Mavaraganes said. "We scraped together some, I was able to amass maybe a teaspoon full in a cup, and he took it with him."

Cars at the police parking lot at Belmont and Western have the rusty powder all over them, too.

NBC5's Mary Ann Ahern said a lot of people in Chicago want to know what the stuff is that has fallen all over their cars.

"Where is this coming from? What effects is it going to have on us?" Mavaraganes asked.

Some suggested the rusty powder came with the recent rain, dirt from the southwest part of the U.S. Lab tests will tell more.

A spokesman for the Illinois EPA said the lab results on the mysterious powder should be in early next week.