MOL chairman-CEO Zsolt Hernádi and Energy Minister István Kapitány are en route, Magyar said.

In a post on Facebook, local news source Tiszaújvárosi Krónika said available information pointed to the explosion of a pyrolysis gasoline line at the MOL petrochemicals plant. Disaster protection officials have said local residents are not at risk, it added.

Dávid Dojcsák, the spokesman for the local disaster protection authority, told state news wire MTI that the fire at the plant was being extinguished and a mobile laboratory had been sent.

MOL told MTI that the explosion took place during a restart of the Olefin-1 plant. Firefighters have localised the fire, it added.

The oil and gas company confirmed that one person had died in the explosion and a several were seriously injured. Experts are investigating the circumstances of the accident, it added.

Update: Hazardous Substance Levels Below Danger Threshold

Tiszaújváros Mayor György Fülöp said in a video message on Facebook that there was no need, for the time being, to take steps to protect local residents. He added that firefighters from Tiszaújváros and nearby Miskolc had been called to the site and were extinguishing the fire and cooling the facility with foam and water cannons.

People injured in the accident are being treated, the spokesman for the National Ambulance Service told MTI. Pál Győrfi said three helicopters and a number of ambulances had arrived at the scene and were evacuating the injured.

In an update on Facebook, the prime minister said one person had died in the accident and seven had suffered serious burns. He added that measurements by the disaster protection authority’s mobile laboratory showed levels of hazardous substances were not over thresholds.

Magyar expressed his condolences to the family of the person who died in the explosion and wished a speedy recovery to those who were injured.

Economy and Energy Minister István Kapitány said in a post on Facebook that the final casualty count in the accident stood at one dead, one seriously injured and seven with minor burns. The person with serious injuries was evacuated by helicopter to a hospital in Debrecen, he added.

The explosion was reported at 8:47 in the morning, Kapitány said.

Update: Fire Extinguished

The fire at the base has been extinguished, the spokesman for the local disaster protection authority told MTI.