Two outdoor graduation ceremonies in Paterson, New Jersey, held during a dangerous heatwave ended with more than 100 people receiving treatment and some being taken to the hospital, authorities said.

People fainted in the crowd at Paterson's Hinchliffe Stadium as temperatures reached dangerously high levels, the city's public safety director said.

Sixteen people were sent to the emergency room for heat-related illness following two New Jersey high school graduations Monday as an extremely dangerous heat wave is underway for the eastern half of the United States.