Machinery from one of Wasteserv's contractors stationed within the Magħtab Environmental Complex caught fire at around 2.30pm.
The Civil protection Department was brought in and managed to extinguish the fire by 3.30pm.
Wasteserv said that no one was hurt.
Last August, a major fire broke out at the Wasteserv plant in Magħtab, prompting a health hazard alarm. The fire was brought under control hours later.