(CNN) -- A dead jellyfish that broke to pieces while it was being removed stung almost 150 people Wednesday at a state park beach in Rye, New Hampshire, police and CNN affiliate WMUR said.
So many people complained of itches and burns that the Rye fire department called in help from five neighboring fire departments, police told CNN.
Most of the beachgoers were treated at the scene. Five children were taken to a hospital, police said.
The incident took place at Wallis Sands State Park.
A lifeguard spotted the jellyfish 100 yards from shore. It broke apart when he used a pitchfork to drag it to the beach, WMUR reported.
A jellyfish retains its ability to sting even after it is beached or dead, scientists say.
"Soon after we got the jellyfish off the beach, people started complaining of rashes and stinging and hurting and then the number just multiplied exponentially," Ken Loughlin, park manager, told WMUR.
Officials ordered everyone out of the water, before bagging the jellyfish -- with its longest tentacle about 13 feet -- and placing it in a Dumpster.
CNN's Chuck Johnston contributed to this report.