Energy giant ExxonMobil has apologised after black smoke from its Fife gas plant blew over nearby homes.
Flames and fumes poured from the chimney of the Fife Ethylene Plant at Mossmoran on Sunday evening as the operators "flared" off waste products.
"Flaring" is common at the plant, but locals have voiced concern after an apparent increase in such activity.
Councillor Darren Watt, who represents the Cowdenbeath ward, said he approached ExxonMobil for answers.
A separate flaring took place last week due to a "process upset".
A company spokesman said: "ExxonMobil Chemical Ltd apologises to the local communities for the flaring at the Fife Ethylene Plant, Mossmorran.
"The flare is an essential part of the plant's safety systems and there is no danger to local communities or employees.
"This flaring is the result of a sudden, temporary disruption to the feedstock process for the plant during the evening of Sunday, June 18.
"This flaring is a separate issue from last week's process upset, which was resolved on Saturday at 09:20 hrs.
"We aim to keep flaring to a minimum and are currently in the process of resuming normal operations.
"We anticipate completion within the next 36 hours."