Environmental protection officers have been deployed to investigate unplanned flaring at a chemical plant in Fife.
ExxonMobil, operators of the Mossmorran site, blamed a “process interruption” for the elevated flare on Sunday.
Plant manager Jacob McAlister apologised and said teams are working to reduce disruption to those who live nearby.
The flaring, which is a safety measure at the site, causes light and sound disturbance.
One woman contacted STV News and said her house had been “rumbling since 3.30am” on Sunday.
She added: “Enough is enough, this is a joke. Sorry for the ranting, but this has went on for years.”
In May this year, the Scottish Environment Protection Agency (Sepa) confirmed it was seeking a prosecution following unplanned flaring at the chemical works in April 2019.
The flare burned for six days and led to more than 900 complaints.
On Sunday, Sepa said it was working with ExxonMobile “to understand the cause of the incident”.
Chris Dailly, Sepa’s head of environmental performance, said: “Whilst limited, controlled flaring is an authorised and important safety feature of industrial sites, we know it has been happening too often at Mossmorran and the community impacts are often significant.
“That’s why we have referred ExxonMobil Chemical Limited to the Crown Office and Procurator Fiscal Service (COPFS) for consideration of prosecution related to the Easter 2019 flaring event and why we have required the installation of noise reducing flare tips by May 8, 2021 followed by the installation of ground flares.
“Whilst we don’t know yet from the company the cause of the latest flaring or expected duration, we will provide further updates as soon as further information becomes available.
“In addition to our fixed air quality and noise monitoring points across the area, officers are deployed to record community impacts at five locations surrounding the site.
“Officers have noted community noise impacts and our monitors continue to demonstrate no breach of air quality standards.
“Our work now across the incident will determine whether there has been a breach of permit conditions and what our next steps will be in line with our published enforcement policy.”