An accident involving gas flaring at a Nigerian crude oil terminal killed one person and injured another, local media report.

Both victims were supervisors at the 4.5-million-barrel capacity Qua Iboe Terminal in southeastern Nigeria. The accident happened Sunday.

The supervisors were restarting a process unit after maintenance. It was decided to ignite a gas flare that somehow exploded, the Nigerian newspaper The Punch reports.

Flaring is a safety procedure in which excess gas is burned off to prevent the buildup of pressure in the unit.

Crude oil from numerous offshore fields is brought to shore at Qua Iboe via a seabed pipeline system. The crude is then loaded onto vessels through a single point mooring extending 23 miles offshore.

ExxonMobil, as field operator, holds 40% interest in the field production mix with the Nigerian National Petroleum Corporation holding the remainder.