Operators of a Fife chemical plant have apologised after neighbouring communities complained of being disturbed by flaring.
US energy giant ExxonMobil said the burn-off at Mossmorran over the weekend was necessary because of a “mechanical issue” with a pump.
But it was unable to “predict precisely when in the next few days” it would return to normal operations.
READ MORE: Final warning letters issued over Mossmorran flaring
The Scottish Environment Protection Agency (Sepa) said it was monitoring after residents reported seeing bright flares and feeling ground vibrations.
The incident occurred just a few weeks after ExxonMobil Chemical and Shell UK were issued with a final warning by the environment watchdog Sepa.
The regulator said the impact of unplanned flaring last June was “preventable and unacceptable.”
Sonia Bingham, manager of the Fife Ethylene Plant, said: “Good progress is being made as our maintenance team and specialist supplier work around the clock to resolve the issue.
“The failed pump is being repaired utilising the available spares needed and we will then commence the commissioning of the pump into operation.”
Sepa said it was organising a full response to the incident.
It issued a statement saying: “Flaring remains an important safety mechanism and is permitted through licence conditions.
“However, in response to the flaring, which began in the evening of Saturday 19 May, Sepa has mobilised a full response.
“The response includes both air quality and noise monitoring to assess the local impacts.”