It cost the Fire Service more than £300,000 to deal with two major fires involving illegally stored tyres in Londonderry last year.
Almost 100 firefighters were involved in one of the operations at Campsie in October.
That operation cost just over £229,000. It later emerged those tyres had been stored illegally.
In August, another fire involving a tyre depot at Pennyburn Industrial Estate cost £106,000 to put out.
Four fire pumps and a specialist foam tender were tied up in that operation
Concerns were raised at the time about the storage of the tyres and the impact both fires had on the environment.
Later today, officials from the Northern Ireland Environment Agency will brief councillors in Derry on their investigations into the fires.