More than a third of the students from Kristie Ainsworth's Barwon Heads primary school class have been diagnosed with cancer or autoimmune diseases.
Ms Ainsworth herself was diagnosed with the blood cancer Hodgkin's lymphoma when she was 17, she has told a Senate inquiry into a possible cancer cluster at Victoria's Bellarine Peninsula.
"There are so many young people who have died," she told the inquiry at Barwon Heads on Tuesday.
Ms Ainsworth and many other residents blame their illnesses on the chemicals used in a mosquito spraying program run by the local council since the mid-1980s.
She said the local streets and parks were regularly fumigated, and described riding her bike to and from school through "foul-smelling, foggy mist".
"We played in it, we basically lived in it," she said.
But Victoria's chief health officer Professor Brett Sutton said health department analysis has not found a statistically significant increase in cancer cases in the Bellarine region, when compared to the rest of the population.
He told the hearing the lack of statistically significant differences in cancer rates "is really not consistent with the introduction of a new or cancer causing material or carcinogen."
The department conducted an extensive analysis for all cancers across all age groups from 1982 to 2019.
"I hope that there is some closure in the reassuring findings," Prof Sutton told the inquiry.
The department estimates for breast cancer and leukaemia rates on the Bellarine were somewhat higher than for the rest of the population, but the inquiry heard these estimates are uncertain.
In his submission, Prof Sutton rejected suggestions that he or the department have a conflict of interest or failed to properly investigate community health concerns.
"This could not be further from the truth," he said.
Bellarine surf shop owner Ross Harrison also gave evidence, accusing the local council of "recklessness of the highest order".
His own data on cancer and immune disease cases in the local community shows that of 196 people who fell ill, 86 per cent of all cases lived or played in the council's mosquito spraying zones.
Mr Harrison criticised the Victorian health department's investigation of the issue, saying the department had included areas that were never part of the spraying program, and failed to take into account historical cases, or holiday makers who spent summers on the peninsula and later became sick.
He also accused the City of Greater Geelong of destroying data relating to the spraying programs.
The council said in its submission that it sympathises with the people who have become ill, but says it can't comment on whether a cancer cluster actually exists.
Nor could it say whether its spraying program is responsible.
"The city is not aware of any science or other evidence to support this suggested link," it said in a submission.
The council's Peter Smith gave evidence and said the practice of "fogging" was not a core part of the mosquito management program.
"The city hasn't been provided with any evidence (chemicals) haven't been used correctly," he said.
He said he was not aware of any council records or staff knowledge that the program had caused health issues.