ROME, Jan. 4 (Xinhua) -- A fire that broke out in a disused warehouse filled with industrial waste in the Pavia area of Italy's northern Lombardy region was probably arson, local media quoted officials as reporting Thursday.

Authorities said the warehouse had no electricity, and low winter temperatures meant no spontaneous combustion was likely, so probably the fire was set on purpose.

Televised images showed a wall of raging flames and black smoke billowing from the charred warehouse located in the countryside near the towns of Corteolona and Genzone.

Mountains of plastic, tires, and other waste had been dumped in the abandoned 2,000-square-meter warehouse. Local residents had seen trucks coming and going from the isolated site, according to media reports.

Pavia Prefect Attilio Visconti said the site "was not known to the relevant environmental permit authorities", meaning that the waste dump was illegal, ANSA news agency reported.

The fire that broke out last night caused a toxic cloud of irritating fumes, which wafted all the way to the city of Lodi and prompted the evacuation of about 100 people from the nearby communities.

Firefighters from the surrounding cities of Lodi, Pavia, and Milan worked overnight to put out the fire.

Local mayors on Thursday urged residents to stay indoors and not to eat produce from their vegetable gardens, RAI public broadcaster reported. This was the eighth such fire in a year in the area, according to RAI.

The Regional Environmental Protection Agency (ARPA) is testing for harmful substances that may have been released by the fire. Results will be available in three days, according to ANSA.