The four-blaze at Chirk's Kronospan factory last month was caused by natural combustion, a fire service investigation has revealed.

The cause was revealed by Wrexham Council last week as the authority looked to address concerns raised by members of the public in the wake of the fire which broke out on January 13 in the timber holding area of the factory off Holyhead Road.

The authority's Public Protection team, which is responsible for regulating the wood panel manufacturer's environmental permit including the wood pile areas of the factory, will now investigate the circumstances surrounding the fire.

A statement issued to Chirk residents said: "This investigation will take time to complete and the outcome cannot be speculated on until all the facts are available.

"All agencies understand the concerns raised in the community following the third fire in three years."

During the fire, members of the public were warned to stay indoors and keep windows closed and children at the nearby schools were kept indoors during breaktimes.

But in the weeks since residents have held protests voicing concerns over safety and a lack of communication in the wake of the incident.

The council's statement addresses several of these key concerns, including air quality monitoring, which is being called for in the Welsh Assembly.

The authority states it will be looking at better ways of communicating with residents in the future.

It has said: "Kronospan issued its first press statement, in agreement with North Wales Fire & Rescue Service, at 10.25am on Monday morning.

"The council took the lead regarding communications on Wednesday, January 15 and from that time regular updates were given via social media and also the print and broadcast media. In addition, the information was sent to the town council, library and leisure centre who all agreed to post a hard copy to their notice boards.

"Communicating with residents involved in such an incident is not easy and we will be looking at other avenues of communications in the coming weeks that could be used should there be a similar incident in the future."

It has also said it will look at reviewing the Chirk Environmental Liaison Group which was set up over 20 years ago which a view to providing "open dialogue between the community

representatives; the operator and the regulating authorities".

The statement adds: "Given the concerns raised by the community after this event, it would

be appropriate to review the function and purpose of this group with aim of improving future

communication and liaison with the community."

And in regards to the lack of air quality monitoring – which took place two days after the incident began – the council has pledged to install equipment that provides real-time monitoring.

It continues: "Air quality monitoring took place from Wednesday, January 15 by Natural Resources Wales and Wrexham CBC has commenced air quality monitoring in Chirk.

"Wrexham CBC will commit to liaise with Natural Resources Wales and Kronospan with the aim of installing air quality monitoring equipment in Chirk that provides real-time monitoring data that can be viewed directly by the community."