Illinois Republican Mark Kirk, whose pursuit of President Obama's former Senate seat has been imperiled by his exaggerations about his military record, is now facing scrutiny about his oft-told story of nearly drowning at age 16.

Though no one is objecting to the near-death experience recounted by Kirk, The Chicago Tribune reported Thursday that the five-term congressman may have embellished his recollection of how he was saved after capsizing his sailboat on Lake Michigan. 

Kirk says his rescue by the Coast Guard inspired him to pursue a career in public service.

Kirk who is locked in a tight battle for the seat with Democrat Alexi Giannoulias in one of the highest-profile Senate races in the country. Obama held the seat for four years before winning the White House, and a Democratic loss would be a major embarrassment to the administration. 

Giannoulias has his own embarrassments to explain, but a witness told the newspaper that Kirk's rescue took place in the afternoon, contradicting Kirk's account that he was on the water as darkness fell.

The paper also called medical experts, who disputed whether Kirk's body temperature could have dropped to 82 degrees, just above the heart-stopping threshold, undermining Kirk's assertion that the rescue came in the nick of time.

The experts told the newspaper that had Kirk's temperature reached 82 degrees, he likely would have been unable to swim and would have lost consciousness.

But Kirk stands by his story, describing it as a life-altering event. 

"I think what is clear is I was so cold that I was close to death," he told the newspaper. 

"This is one of the most important events in my life. I was not as well-focused before this event but very well-focused after, aware of your own mortality," Kirk added.

Last month, Kirk apologized for being careless and making mistakes about his military accomplishments. He told supporters that he isn't perfect and pledged to do better.