An investigation has been launched into two explosions at ExxonMobil's Mossmorran plant in Fife.

It is understood the blasts happened on two separate occasions in two different boilers in August.

The blasts occurred as pipes became over-pressurised and burst, and there were no flames.

A Health and Safety Executive (HSE) spokesman said an investigation into two explosions at the plant was currently ongoing.

The plant was temporarily shut down for repairs on 12 August and will remain closed until at least November.

ExxonMobil said at the time that two of the plant's three boilers had failed but made no mention of an explosion.

The firm has since announced it plans to spend £140m improving the reliability of the plant.

'Mistrust and fear'

Linda Holt, of Mossmorran Action Group, said an HSE official had described the incident as a "catastrophic breakdown" at a working group meeting earlier.

Ms Holt said she was "shocked" to learn that the two boiler breakdowns in August were both accompanied by explosions.

She added: "We were also told that neither HSE nor Exxon have so far identified the cause.

"Rumours have been circulating locally that the boilers exploded, and HSE's confirmation makes a mockery of ExxonMobil's communication strategy.

"For years local communities have lived with the fear of an accident at the plant; trying to hide explosions behind an announcement of £140m investment will only exacerbate local mistrust and fear."

In July, the plant was issued with an improvement notice over the risk of an explosion.

At the time the HSE said ExxonMobil had failed to take all measures necessary to reduce the risk of "firebox explosion from furnaces".

The firebox is an area in the plant's furnaces where fuel is burnt.

Stuart Neill, external affairs manager for ExxonMobil said: "We are concerned that comments have been made publicly on an ongoing regulatory investigation.

"It would be inappropriate for ExxonMobil to comment until the HSE's investigation, and our own, have been completed."

Lesley Laird MP for Kirkcaldy and Cowdenbeath said: "Because of the investigation our discussion was limited in scope but it was clear these were very serious incidents and lines of enquiry are complex, particularly in terms of the sequencing of events.

"HSE confirmed no-one had been hurt in either boiler incident, both of which were caused by a critical build-up of pressure in the units."