SCOTLAND'S environment agency is investigating "disappointing" unplanned flaring at the Mossmorran chemical plant.

ExxonMobil Chemical Limited raised the alarm about the incident at the site in Fife shortly before 3pm on Tuesday.

The Scottish Environment Protection Agency (Sepa) said it understands the flaring is due to a trip of a major compressor, and initial reports suggest elevated flaring may continue overnight as the company works towards a safe restart.

It comes after the plant was restarted two weeks ago after upgrades which cost £140 million. 

Exxonmobil were in talks with council leaders in October over compensation for residents living near the Fife plant during five days of unplanned flaring at Easter.

The petrochemical firm said it had had a constructive discussion and would engage in any future formal proposals.

The Scottish Environment Protection Agency received an "unprecedented" 600 complaints about the event.

ExxonMobil then blamed the flaring on a fault in a section of cable.

Chris Dailly, Sepa's head of environmental performance, said of the latest incident: "Having been clear that flaring must become the exception rather than routine, we're disappointed that flaring by ExxonMobil Chemical Limited has occurred again so soon after the restart.

"Officers made immediate contact with the company and we understand that the flaring relates to a trip of a major compressor.

"In understanding that flaring is likely to continue overnight as the site moves to a safe restart, officers will continue to deploy and air and noise monitoring continues.

"Sepa is requiring a detailed briefing on the nature of the current incident and we expect the company to provide timely updates to the community.

"Whilst recognising that flaring is an important safety mechanism, this is a further reminder of why the short and medium-term steps being taken by Sepa to mitigate flaring is so critical, including noise-reducing flare tips in 2020/21 and bringing forward plans for fully enclosed ground flares."

Sepa officers are responding and air and noise monitoring continues to be deployed.

In September 2019, the company announced a £140 million plan to reduce such occurrences and improve infrastructure at the plant.

The previous month Exxonmobil chose to temporarily close its plant to undertake maintenance on its boilers in August and said it should reopen by the end of the year.

That came after Sepa launched a formal investigation into unplanned flaring at the plant last April following hundreds of complaints from residents about a chemical smell and rumbling noise.

A statement issued to the local community by the company said: "We have, unfortunately, experienced a trip on one of our major compressors.

"Our team is currently undertaking the necessary checks to begin a safe re-start."

The process of flaring involves burning off gas that cannot be processed. 

Although the technique is legally permitted, it causes significant light and noise pollution which the operator is obliged to minimise.

Exxonmobil added:"In order to keep the rest of the plant running and reduce total duration of flaring, we need to manage this process through our elevated flare.

"We are also working with our neighbours Shell to maximise ground flare capacity.

"The use of the flare is completely safe, and we will continue to keep you updated as we work our way through this process.

"We apologise for any inconvenience to our local communities."