"My husband hit both of his feet and sliced one of them open to the bone, I unfortunately hit my knee and also sliced my knee open to the bone."
Cossar and her husband completed the swim, and she said it was only upon reaching the finish line that they realised the extent of their injuries.
"Yeah, a bit of shock that it was quite that bad, I think the adrenaline was starting to wear off," she said.
"Then I think when we saw the extent of the other people ... there were some people who looked like they were going into shock, who looked quite bad."
Cossar said all of the event volunteers were really helpful, and first aid was being provided.
However, she said the St John first aid van was still at the race start point, with Cossar understanding it had been held up attending injuries.
St John paramedic delayed on start line
Event director of the New Zealand Ocean Swim series Scott Rice said there were two St John paramedics at the event.
One was at an emergency rendezvous point near the finish line for major medical incidents, with the second stationed at the start line.
That paramedic was set to make the trip to the finish line, but Rice said they were slightly delayed while assisting a swimmer at the start.
"Once we realised that, we used our own medical supplies to assist and we called in the advanced paramedic from the rendezvous point to make their way round to assist any affected swimmers as soon as we possibly could."
Rice said his team had asked for a third St John paramedic to attend earlier in the week, but one was not available.
He said contact been made with 15 injured participants to see how they were getting on.
"They're good, some of them have got the medical attention they needed just to patch themselves up, but they're all in good spirits ..."
He said the people had really enjoyed the event, and many would be back for more.
This particular course had only ever been used once before in 2019, but there were no reports of injuries during that race, Rice said.
The events briefing process was now being reviewed along with the structure for people to enter the water, and the water entry itself.
Rice said that would help to reduce the risk of anything like this happening again.
Cossar said Rice had contacted her husband and had apologised for the situation.
"He was very good, he was very apologetic and said that they were doing a review."
She and her husband had been discharged from hospital after receiving orthopaedic surgery and were planning to fly home to Wellington.
St John head of event health services Simon Barnett said no patients required transport to hospital after the Swim the Bridge event.
"As is typical with large events, our ambulance officers treated a small number of participants for a range of minor ailments, in particular, foot injuries."
He said St John had worked with Quantum events for the last 15 years to provide professional medical coverage at multiple events throughout the country.
- RNZ