BUENOS AIRES (Reuters) - An explosion at a grains terminal in Argentina owned by China’s COFCO International on Wednesday killed one employee, injured others and affected shipping activities from one of the world’s top food suppliers, the conglomerate said.

The cause of the blast is not yet known but it could have an outsized impact on the flow of food exports from Argentina as unions representing grains inspectors and crushing workers said they would go on strike on Thursday to demand better safety conditions.

Television images showed thick black smoke billowing from what COFCO described as a 52,000-square-meter grains processing plant. The facility is part of Argentina’s shipping hub of Rosario, on the Parana River in Santa Fe province.

“COFCO International can confirm that an explosion occurred at the loading area of its facilities at Puerto General San Martin in Rosario,” the Chinese state-run conglomerate said in a statement.

One employee died in the blast, the statement said, and eight others were taken to hospital for treatment.

“The cause of the incident is not yet known,” the statement said. Police, firefighters and other authorities provided no additional details.

“The affected site has been shut down,” it said, adding that COFCO had launched “a full internal investigation.” The storage and crushing facility received 27,000 tonnes of grain per day.

It has grains warehousing capacity of 295,000 tonnes and soymeal storage capacity is 105,000 tonnes.

The plant was previously owned by Dutch grain trader Nidera, which COFCO agreed to buy in 2014. This acquisition and other mergers projected COFCO into some of the world’s top grain, vegetable oil, sugar and coffee producing regions.

Argentina is the world’s top exporter of soymeal livestock feed as well as a major supplier of corn and raw soybeans. Soy is in high demand in China from a growing middle class eating meal-fed beef and pork.

Some 80 percent of Argentina’s agricultural exports are sent from Rosario. Cargo ships loaded at the hub sail down the Parana on their way to the shipping lanes of the South Atlantic.