Excerpts from abc7chicago.com:

An off-duty Chicago firefighter died on Sunday morning after being pulled out of Lake Michigan at 31st Street Beach. 

CFD responded to the beach about 7:30 a.m. for a call of a marine distress, and crews pulled a man from the water, who was in critical condition.

Sadly, the man, later identified by his family as Wilbert Hayes, did not make it. It was not immediately clear what led to his distress. 

Hayes, who had just ended a shift with the Chicago Fire Department before going to the beach with his family, died at University of Chicago Medical Center. He had been on the job since 2009.