Ill-health has not always been Mcephe's constant companion - he insists he was a healthy man before he started working for the South African Nuclear Energy Corporation (NECSA) at the state-owned Pelindaba nuclear reactor, about 40km from Johannesburg.
NECSA promotes research and development in the field of nuclear energy and radiation sciences and technology, and processes special nuclear material and restricted material. Apart from its main operations at Pelindaba, the corporation also operates a radioactive waste disposal facility.
"I spent years working hard as a labourer in Pelindaba nuclear facility, and I was fine at the beginning, but we used to load chemicals onto tractors and do a lot of maintenance work on broken pipes that funnelled liquids around the complex," he said.
"We were never told about the risk of radiation contamination and there was never any safety training given to us - my protective clothing consisted of a pair of overalls. Now I am consumed by diseases. Things are bad, so bad I have to go to the clinic every month for treatment."
For 13 years Mcephe worked long, arduous days as a labourer at Pelindaba until his retrenchment in 1999. Today, he is one of a growing group of former NECSA employees who claim their ill-health is directly linked to their time as employees at NECSA's nuclear facilities.
His former employers ignored his complaints, so he contacted Earthlife Africa (ELA), an anti-nuclear group. A medical and occupational history examination concluded that his symptoms were consistent with those of someone who had been exposed to harmful chemical substances or radioactive materials.
According to ELA, hundreds if not thousands of former NECSA employees are in the same position. The results of a new survey, commissioned by ELA and carried out by Health Gap Network, a health-rights advocacy group, reviewed the medical condition of 208 of them, including Mcephe.
The findings claimed that 72 of the 208 people in the sample group were suffering from probable occupation-related illnesses, ranging from respiratory diseases, like lung cancer, asthma and lung fibrosis, to dermatological conditions.
In his final report, senior reviewer Dr Murray Coombs concluded that in an industry where annual medical surveillance is a legal requirement, the figures appeared to be extremely high.
"If we even accept that only 50 percent of the 72 [present] problems of potential occupational diseases, it may indicate 5,100 employees with occupational disease [in the historical pool of 30,000 NESCA employees since South Africa's nuclear programme began in the 1960s]," he wrote in his report.
The results add weight to fears harboured by South African anti-nuclear groups about safety at the country's nuclear power facilities. "We want to prove the company has been negligent in the past, and that the 1,073 workers currently employed by NECSA could still be exposed to potentially hazardous substances," said ELA's Mashile Phalane.
"We have been receiving anecdotal evidence for years in relation to radiation contamination at Pelindaba. To date around 350 people have come forward to say they are suffering ill-health that is linked to their time there, but many more won't come forward because their medical expenses are being looked after by the company, consequently they don't want to rock the boat."
ELA maintained that health concerns alone should spur the government to review the direction of its nuclear power programme. Future projects include a radioactive fuel plant, and a second reactor to be built by Eskom, the state electricity utility. NECSA has mooted a smelter to process radioacti