Rescuers were still searching for survivors at the site in the town of Virrey del Pino, some 40 kilometers (25 miles) west of Buenos Aires, yesterday.
Emergency management authorities said they could not rule out the possibility that more people had been killed in the explosion, which may have been caused by a gas leak.
Among the wounded were four minors including a three-year-old who was admitted to a regional hospital with multiple injuries and burns.
"There were several people inside. Rescuers are working to see if anyone is alive," said Patricia Spinelli, emergency director for the province.
A gas leak at a nearby facility that produces gas cylinders and fire extinguishers may have caused the explosion, an official said.