Health experts are analysing claims Mossmorran flaring has caused a medical symptoms including migraines and breathing problems.
NHS Fife said its public health team is poring over hundreds of reports to environment agency Sepa from worried residents near the Cowdenbeath plant.
The team is looking at issues raised and is to publish its findings in September.
People have complained of burning eyes, being short of breath, headaches and hay fever-like symptoms during flaring at the gas plant.
During flaring earlier this year NHS Fife warned GPs they may see an increase in visits from people with health problems they believed were connected with flaring.
However, the health authority said no practice had flagged up any concern.
An NHS Fife spokeswoman said: “We recognise that during incidents of unplanned flaring complaints to Sepa’s helpline indicate an increase in concern amongst residents about health concerns.
“NHS Fife’s public health team are working with Sepa to analyse these health-related complaints and identify the issues raised.
“This information will be made available to the public when the analysis is complete, which will be in September.”
Mossmorran Action Group has called for an independent study of the health, social and environmental impact of the plant.
Chairman James Glen said: “Residents have complained that Mossmorran has been affecting their health for decades.
“Since we opened our social impact map in 2017 we have received 340 separate reports of health impacts on local residents during bouts of flaring, ranging in severity from migraines and asthma attacks to anxiety and insomnia.
“NHS Fife has failed to address the issue and do not have the resources in place to capture and collate data on health impacts.
“This means any analysis they produce will be of limited value, and unlikely to command public confidence.”
Flaring is a safety mechanism used during process upsets but the light, noise and vibration can cause severe disruption to those living in the vicinity.
ExxonMobil Chemical runs the Fife Ethylene Plant at the complex.
Stuart Neill, external affairs manager, said an independent air quality study indicated impact on air quality and human was unlikely even in worst-case scenarios.
He said: “Independent air quality monitoring has, over many years, consistently shown that the Fife Ethylene Plant and flaring pose no significant risk to the health of the community.”
Teresa Waddington, manager of Shell’s Fife NGL Plant, said: “We monitor our emissions in line with our pollution prevention permit and we provide information to a local air quality monitoring review group.
“This group, which includes representatives of the local authorities, continues to find and report annually that emissions from the plants at Mossmorran pose no significant risk to the health of local residents.
“We are aware of further assessment being done by NHS Fife and Sepa and we are very open to any evidence being shared, and further dialogue.”
