A girl was injured after falling off a seafront ride called The Rocker.
Comments were made about the incident on Facebook with one woman claiming the girl involved was in an induced coma, although police said they believed this was not the case.
Other people were on the ride when the incident happened.
They said police taped up the ride afterwards.
One person said: “Just saw a young girl fall out of a ride on the sea front in Worthing from the top. Hit her head and bust her ankle.
“They have not died and only one ride was closed off and tapped up.”
Sarah Felton added: “Her ankle was broken as bone was popping out but also hit her head pretty hard so was bleeding.
“My partner ran over there to make sure she was breathing and he ended up saving her life.
“She’s in hospital so she is in safe hands.”
Rosie Katie Culver added: “The ride stopped and everyone had to get off immediately.”
Grace Ridge-Edwards added: “I witnessed everything and I can assure you she did not try to climb out.
“She passed out into the empty seat next to her and the power of the ride caused her to fly out.”
Katie Rose Hockley said: “I was on the ride when it happened I heard a big bang and I looked over and a woman was on the floor, she had dropped from the highest point and banged her head and ankle on the metal.
“Police and ambulances came and it was bad and I'm shook up.
“Never going on a fair ride again.
“We all got taken off the ride immediately.”
Nicola Chapman said: “Oh my God my son just saw someone fall from the top of one if the rides at the fair.”
A Sussex Police statement said: “A police unit was on patrol on Marine Parade in Worthing seafront at around 9.30pm on Thursday when they were made aware of an 18-year-old woman who had fallen from one of the fair rides.
“They provided initial first aid and paramedics arrived soon after to give further medical assistance.
“The woman was taken to the Royal Sussex County Hospital in Brighton with a head and ankle injury where she is still receiving medical treatment.
“Police cordoned off the scene and spoke to witness.
“Sussex Police is liaising with the Health and Safety Executive who will be conducting their own investigation.”
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