A 30-year-old runner collapsed at the finish line of the Brooklyn Half Marathon and died, NYPD said Saturday.

The man collapsed just before 9 a.m. and was taken to Coney Island Hospital, where he was pronounced dead, according to police. The death is being investigated as a possible cardiac arrest, officials said.

"The male runner, age 30, collapsed after finishing the race," race organizers the New York Road Runners said in a statement. "He was immediately attended to by on-site medical staff and then transported to Coney Island Hospital. NYRR has medical staff placed from start to finish throughout the race course, who are ready to respond immediately to the medical needs of all runners, spectators, volunteers and staff."

The FDNY said 15 other people were sent to the hospital with injuries. 

Temperatures Saturday reached 90 degrees, with a heat index pushing 100. Both a heat advisory and an air quality health alert were in effect, the latter instituted because of high levels of air pollution.