A blaze engulfing the coal-fired Ferrybridge C power station in the UK’s West Yorkshire region is a “serious incident” that required 15 fire crews to quell it, plant owner SSE said on Thursday.

The fire that broke out at about 2 p.m. and impacted Units 3 and 4 at the power station activated emergency response procedures, the utility said. By 5 p.m., fire crews were still battling the blaze. Onlookers tweeted that the fire caused traffic disruptions and dramatic photos showed thick black smoke billowing from the power station.  At 6:30 p.m., SSE said the fire has been “brought under control.”

All personnel have been accounted for, and no injuries have been reported.

According to the utility, both affected units had been operational over the summer but had been in scheduled shutdown for maintenance when the incident began on Thursday.

Early indications showed that the fire itself began in Unit 4. “Currently we do not expect Unit 4 to return to service in this financial year.  Unit 3 is not expected to return to service before 1 November. Our immediate priority is to manage the incident and to ensure the safety of staff, contractors and the general public,” SSE said in a statement.

The Ferrybridge power station is situated on the River Aire, in West Yorkshire. It is the third coal-fired power station to be built on the site since 1924. The power station, often referred to as “Ferrybridge C,” first fed electricity to the national grid in February of 1966.

The plant’s 490-MW Unit 1 and 490-MW Unit 2 were opted out of the European Union’s Large Combustion Plant Directive and permanently shuttered once they used up their allowed 20,000 operating hours at the end of March 2014.

Unit 3 and Unit 4, 490 MW each, have been retrofitted with flue gas desulfurization technology to enable them to comply with the directive and are expected to operate until at least the end of 2020.

A new 68-MW multi-fuel generation plant is currently being constructed at the Ferrybridge site as part of a £400 million joint venture between SSE and Wheelabrator Technologies. It is unknown how this project, slated to come online in 2015, has been affected by the blaze.

Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)