Federal safety regulators are issuing safety tips for when purchasing air purifiers as Canadian wildfire smoke continues to spread into the U.S.

Smoke from the wildfires is spreading throughout most of the Great Lakes region and as far as Missouri and Kentucky on Wednesday. 

The Consumer Product Safety Commission (CPSC) tweeted six tips for consumers to keep in mind when seeking out air purifiers.

COLORADO WILDFIRE DEVOURS NEARLY 3K ACRES AS RED FLAG CONDITIONS CONTINUE

For one, the CPSC is reminding consumers that these machines should be plugged directly into a wall rather than a power strip or extension cord. 

Consumers should also purchase air purifiers with HEPA filters that meet the Association of Home Appliance Manufacturers (AHAM) standards, the CPSC added. 

These standards help "preserve the safety, efficiency and performance of major, portable and floor care appliances," according to AHAM's website. 

Ozone-generating air purifiers, though, should be avoided, regulators said.

FAA DELAYS FLIGHTS FOR 5 MAJOR US AIRPORTS SO FAR, AS CANADA WILDFIRE SMOKE IMPACTS VISIBILITY

In order for the machine to be effective, the filter also needs to be changed out when instructed, the CPSC said.

As of Wednesday, the Detroit area is facing some of the worst air quality in the U.S. 

The Environmental Protection Agency’s AirNow.gov site warned that everyone in the area "should stay indoors and reduce activity levels." 

Meanwhile, Chicago, Indianapolis, Cleveland, Ohio; and Pittsburgh all have "very unhealthy" air. A wider circle of unhealthy air spread into St. Louis and Louisville, Kentucky.

GET FOX BUSINESS ON THE GO BY CLICKING HERE

Chicago Mayor Brandon Johnson urged young people, older adults and residents with health issues to spend more time indoors and pledged "swift action to ensure that vulnerable individuals have the resources they need to protect themselves and their families."

The Associated Press contributed to this report.