Department spokesperson Zolisa Sigabi said the inquiry, which resumed on Monday at the Cato Ridge Country Club, would continue despite "tensions between workers and manganese company Assmang over the company's alleged threats to dismiss seven employees who are suffering from manganism."

Jan Steenkamp, chief executive of African Rainbow Minerals — one of the stakeholders in Assmang — could not immediately be reached for comment on the allegations.

Sigabi said: "The Department is targeting June 2008 to wrap up the inquiry as it has already gathered most of the information needed."

On Monday the inquiry heard evidence from occupational hygienist Edgar Waller, who had assessed risk at Assmang every two years since 2003, that respiratory equipment had been made available to staff during his visits.

However, he pointed out that staff did not always wear their masks.

He said that it was possible for staff to "sabotage" equipment and that the movement of staff in and around the furnaces of the ferromanganese smelters could distort results of testing for manganese dust.

Manganism is acquired by overexposure to airborne manganese and is a disease that affects the sufferer's central nervous system, leaving him with symptoms very similar to Parkinson's disease and multiple sclerosis.

Sapa