Black smoke billowing from a gas plant in Fife is causing health problems for people living nearby, the NHS has warned.
ExxonMobil was forced to apologise after waste burned at the facility near Cowdenbeath caused a noxious cloud to blow over the town last month.
The US oil giant insists there was no danger but NHS public health consultant Dr Chris McGuigan said a "range of symptoms" have been reported.
Complaints include breathing difficulties, eye irritation and difficulty sleeping, he said.
NHS Fife has called for action and environmental protection agency Sepa, which previously fined ExxonMobil a record £2.8m for emissions from the plant, has launched an inquiry.
Dr McGuigan said: "We already know of at least one instance where emission of black smoke from flaring at Mossmorran exceeded the 15-minute limit imposed as an operating condition.
"We are pleased that Sepa has committed to a full investigation, which will look at the causes of the incident and the steps being taken to ensure it does not happen again.
"We are also hearing people have been experiencing a range of symptoms which they relate to the flaring, such as breathing difficulties, irritated eyes and even disturbed sleep due to the noise accompanying the flaring.
"Clearly this is a distressing and worrying situation for the community and we would advise anyone experiencing symptoms that they believe may be related to the flaring to get help."
Flaring - the controlled burning of waste - is carried out as a safety measure at the Mossmorran plant.
Activists believe it is happening increasingly often, however, reporting that a recent burn lasted for nine days.
Local MSPs have urged the government to intervene and members of the Mossmorran Action Group plan to hold a meeting this week to discuss their concerns.
Co-founder Katrona Turner said: "There needs to be a public debate about the facilities.
"For 32 years, Auchtertool residents have regularly suffered negative impacts ranging in severity from one of Europe's largest ethylene facilities.
"Speaking to our neighbouring communities, they have faced the same issues and it is time for the operators and the authorities to put our communities, our families and friends, at the heart of long overdue investigations and mitigatory action.
"We need definitive answers to our collective concerns."
Ethylene is produced at Mossmorran through a process which heats ethane feedstock to temperatures of almost 900C and then cools it to -150C.
Gaseous by-products are fed into the plant's furnaces, making it party self-sustaining.
Last month's incident at the plant was reportedly caused by sudden expected disruption to the process.
Gina Hanrahan, acting head of policy at environmental organisation WWF Scotland added: "It's important to see regulators taking the communities' concerns about noise and health impacts seriously.
"We need to have confidence that corporations like ExxonMobil are complying with pollution rules to keep local people and local air quality safe."