(Twitter photo / @Liveuamap)

Four people were hospitalized with cuts and other injuries after a powerful explosion ripped through a chemical factory in the northwestern Russian city of Kingisepp.

The blast destroyed a two-story building at the Polyplast plant in the city, 140 kilometers southwest of St. Petersburg, Leningrad Oblast Governor Aleksandr Drozdenko said.


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Drozdenko said the explosion was most likely set off by sparks flying from a grinder operating near a barrel containing the flammable chemical compound saltpeter.

Rescue teams, police, local authorities, and environmental hazard teams rushed to the site, and the explosion was under investigation.

The Polyplast plant is a part of a larger industrial complex and employs about 185 people. It produces chemical ingredients used in construction materials.

Kingisepp has more than 46,000 residents and is located close to the Estonian border.

Featured image: (Twitter / @Liveuamap)

This article originally appeared on Radio Free Europe/Radio Liberty. Follow @RFERL on Twitter.