RIO DE JANEIRO, Feb 18 (Reuters) - Nine workers at a fertilizer plant owned by Brazilian mining company Vale SA were sickened by an ammonia leak on Wednesday, company and union officials and local authorities in Araxa, Brazil said on Thursday.
While the workers were overcome by the fumes and taken to hospital, all have been released and are in good health. On Thursday, the plant was operating normally.
The leak was from an ammonia system control valve, the local, company and union officials said.
Union officials said the leaks and other safety problems are endemic at the facility and show that the plant is out of date.
Vale said the allegations are not true.
Vale is the largest producer of phosphate and nitrogen fertilizers in Brazil.
Ammonia, a mixture of hydrogen and nitrogen, can at high concentrations cause lung damage and death. At the Vale plant, it is used to make nitrogen-based fertilizers.
Nitrogen, along with phosphorous and potassium, are the three main plant nutrients. (Writing by Jeb Blount; Editing by Bernadette Baum)