An explosion ripped through a refinery and fuel terminal operated by Gunvor Energy at the Port of Rotterdam on Thursday, killing at least one person and injuring several others, Dutch police said, according to NBC News.

The blast happened around 11:30 a.m. local time on the Moezelweg, in an industrial section of the port, while a maintenance crew was working on a section of pipes, per the Washington Post. Police described the explosion as "appearing to be a workplace accident for the time being," though a crime scene has been established while investigators work to confirm the cause.

Thursday's explosion was the third major emergency response inside the port area in a matter of hours — it followed a malfunction reported earlier in the morning at a nearby ExxonMobil refinery, according to NL Times.

Europe's largest port

The Port of Rotterdam is the largest seaport in Europe and one of the busiest in the world, handling roughly 450 million tons of cargo a year and hosting a dense cluster of oil refineries, chemical plants and fuel-storage terminals along its Europoort industrial zone. Gunvor, a major independent energy trading and refining company, operates one of several refineries clustered in that stretch of the port.

Emergency crews cordoned off the affected area following the blast, and video from the scene showed heavy smoke rising over the industrial waterfront. Local authorities have not yet said whether nearby residents faced any air-quality warnings, though Dutch outlets reported a temporary loss of power in parts of the surrounding industrial zone following the explosion.

Investigators are working to determine what set off the blast and whether the pipe maintenance work underway at the time played a role. No details on the identities of the victim or the injured had been released as of Thursday evening.