A second employee has died as a result of an explosion Wednesday at an Argentine grains terminal owned by Cofco International, Bloomberg reports.

All operations at Puerto General San Martin are still suspended as an investigation into the cause of the blast has been launched.

The Hong Kong-based conglomerate is cooperating with local authorities and it is unknown when operations can resume, Bloomberg reported.

Seven workers remain in hospital, while one of the injured employees has been released.

An employee with Cofco who identified himself as a receptionist without giving his name declined to comment further on the explosion.

Reuters reported Thursday that the accident could impact flow of food exports from Argentina as unions representing grain workers said they would strike for better safety conditions.

Television images showed thick black smoke billowing from a 52,000-square-metre grains processing plant. The facility is part of Argentina's shipping hub in Sante Fe's Rosaario, Reuters said.

Cofco has confirmed the blast happened at the plant's loading area.

Alejandro Vega, correspondent for P&I Club in Argentina, has said the blast occurred in a horizontal silo, and approximately 15 people in total were hurt.

The facility, bought by Cofco from Nidera in 2014, can store 295,000 tonnes of grain and 105,000 tonnes of soymeal and accepts 27,000 tonnes of grain per day.