The Federal Communications Commission is reportedly investigating whether certain smartphones from Apple and Samsung emit higher levels of radiation than the agency allows, as an independent test carried out by the Chicago Tribune found.

Specifically, Apple's iPhone 7 and iPhone 8 and Samsung's Galaxy S8, Galaxy S9, and Galaxy J3 were found to emit higher levels of radiation than they're supposed to.

Apple and Samsung said they comply with FCC regulations.

The health risks of smartphone radiation are still uncertain.

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The Federal Communications Commission is said to be investigating certain Apple and Samsung smartphones that a Chicago Tribune test last week found emitted higher radiation levels than the FCC allows.

With the help of the radiation testing lab RF Exposure Lab in California, the Tribune found that Apple's iPhone 7 and iPhone 8 and Samsung's Galaxy S8, Galaxy S9, and Galaxy J3 emitted radiation levels beyond the FCC's limits.

The excessive radiation levels were mostly recorded in tests that simulated the phones at 2 millimeters away from a human body — so when someone holds up a phone to their ear during a phone call, or when the phone is in their pocket.

The Tribune noted that it tested only 11 smartphones among the hundreds that are available to buy today.

Read more: Samsung phones have the best screens, but they're set to a lower resolution than they're capable of by default — here's why

The health risks associated with smartphone radiation are still uncertain. Some say that young children and teenagers can be exposed to more smartphone radiation than older people, as smartphones are becoming more ubiquitous. Meanwhile, regular cellphones that emit radiation were around long before smartphones.

Apple told the Tribune that its testing was inaccurate compared with the company's own testing and that it complies with FCC regulations. Apple did not immediately respond to Business Insider's request for comment.

"Samsung devices sold in the United States comply with FCC regulations. Our devices are tested according to the same test protocols that are used across the industry," Samsung told Business Insider in a statement.

The FCC did not immediately respond to Business Insider's request for comment.

The RF Exposure Lab, where the Tribune's tests were conducted, "is recognized by the FCC as accredited to test for radiofrequency radiation from electronic devices," the Tribune said.