NEW YORK — A 32-year-old runner collapsed at the Coney Island finish line of the Brooklyn half-marathon race and died at a nearby hospital on a sticky Saturday morning where 16 other participants were injured, authorities said.

David Reichman of Brooklyn died at Coney Island Hospital, becoming the second runner to die during the race since 2014. He went down while finishing the run on a spring day when the humidity hit 74 percent with temperatures in the 70s.

Fifteen other runners were treated for assorted injuries at the same facility after the annual 13.1-mile run from the Brooklyn Museum to the neighborhood’s famous boardwalk, authorities said, with a 16th refusing medical attention along the route.

Runner Mike Choy, 35, of Staten Island, said the weather made the run more challenging than usual.

“Some guy couldn’t stand, and he fell twice,” recounted Choy. “At first I thought he was drunk, and they brought the paramedics over. It started getting hot for me when we got to Ocean Parkway, and that’s when I had to slow it down.”

Fellow runner Jason Rawlins, 40, agreed the conditions toughed up as the race continued.

“The weather wasn’t bad because we got an early start,” he explained. “It didn’t really pick up until the last couple of miles. I wish them all a speedy recovery. There were lots of hydration stations, lots of spritzing going on.”

Five of the injuries were listed as serious, while the others were listed as minor or non-life threatening, according to the FDNY EMS response and operations at the race.

Runner Tracy Williams, 40, of Brooklyn, reported no issues with the weather.

“I love the heat, so this is easy,” said Williams. “Just stay hydrated, try to get in the shade as much as possible.”

The New York Road Runners website warned of high heat and humidity before the race that began at 7 a.m., the first time the Brooklyn event went off in three years due to COVID-19. Nearly a dozen ambulances were lined up Saturday near the finish line.

“We are deeply saddened by the passing of a participant following the 2022 RBC Brooklyn Half,” the New York Road Runners said in a statement. “He was immediately tended to by on-site medical staff and then transported to Coney Island Hospital … The healthy and safety of our runners, spectators and staff remain the top priority for NYRR.”

An air quality alert was also issued by the National Weather Service beginning a few hours after the run started.

A parking lot attendant working near the finish line said some runners clearly failed to heed the cautions regarding the forecast or the need to hydrate.

“Pay attention to those warnings,” said the man known as Delaware Dave. “They are given for a reason. We knew it would be extremely muggy because there was no wind.”

Story by Thomas Tracy, Liam Quigley and Larry McShane, New York Daily News