An oil production and storage vessel exploded off the coast of Nigeria early on Wednesday with 10 crew members on board though it was not yet clear if there were any casualties or how much crude might have spilled into the sea.

In a statement on Thursday Nigeria’s Shebah Exploration & Production Company Ltd (SEPCOL) said that flames had engulfed the Trinity Spirit floating production, storage and offloading (FPSO) vessel following the blast a day earlier.

But we can confirm that there were 10 crew men on board the vessel prior to the incident and we are prioritising investigations with respect to their safety and security,” SEPCOL Chief Executive Ikemefuna Okafor said in the statement.

The Trinity Spirit can process up to 22,000 barrels of oil a day and can store up to 2 million barrels at any one time, according to SEPCOL’s website

The statement however did not say if any casualties have been recorded or the quantity of oil spilt into the sea.

One industry source active in Nigeria’s oil sector said the vessel had about 50,000 barrels in storage and was not pumping crude from the Ukpokiti oilfield at the time of the explosion.

BP’s Deepwater Horizon oil rig was pumping tens of thousands of barrels a day when it exploded in 2010. By the time the well was plugged 87 days later, 4 million barrels of crude had flowed into the Gulf of Mexico causing an environmental disaster.

“We got information of the fire incident yesterday and we immediately ordered our field officers to commence investigation. Investigations are still ongoing,” Gbenga Komolafe, NUPRC’s chief executive, told Reuters.

“It is only after when we have received the report of this investigation from our team that we will issue a comprehensive statement devoid of speculation,” he said.

SEPCOL’s Okafor said investigations were underway to establish the cause of the explosion while attempts to contain the situation were being made with help from local communities and U.S. oil firm Chevron  (CVX.N), which has a facility nearby.

The Trinity Spirit is the primary production facility for OML 108 which covers 750 square km (290 square miles) of water off the Niger Delta, ranging from a depth of 30 metres to 213 metres, SEPCOL’s website said.