Gardaí confirmed yesterday they are treating a fire at the Cork Metal Company, which destroyed a scrap metal recycling plant, as suspicious.
A security guard went to investigate shortly after 9pm on Sunday when he heard an explosion on site and saw two youths running away.
Plumes of black smoke could be seen in Ballincollig six miles away. Firefighters used specialist height equipment to pour water down on the fire as flames leapt over 100 feet into the air.
Five units of the Cork City Fire Service fought the blaze for several hours until they managed to bring in under control early yesterday morning.
Concern has been expressed about the environmental impact of the fire, which appears to have been centred in a large mountain of scrap metal.
Cork Green Party TD Dan Boyle said the Environment Protection Agency must be seen to act. "When you are talking about things that happen on this scale with the type of materials we are dealing [ with] we should have a seven-day 24-hour service.
"The sooner the EPA realises that the sooner public confidence will begin to occur in that agency, because it certainly doesn't exist at the moment." A previous fire at the plant took two days to be brought under control.
Cork Metal Company is owned by the O'Sullivan family and collects materials for export to Spain. It works mainly with the region's pharmaceutical and chemical industries, exporting hundreds of tonnes of metal each week.