Anil Laad, Disaster Control officer of the Kalyan Dombivali Municipal Corporation (KDMC) said the blaze erupted at around 5.30 PM.
The dumping yard is of KDMC.
Officials said no one was injured in the blaze.
Chief of Regional Disaster Management Cell of Thane Region Santosh Kadam said at least 12 fire tenders, including some from neighbouring towns of Thane, Bhiwandi, Ambarnath and Ulhasnagar, were pressed into service and efforts were on to douse the fire, he said.