Story by Nyasha Makota
CONCERN is mounting over the widespread use of calcium carbide by small-scale welders in Gazaland Industrial Area, Harare, with experts warning that the cost-cutting practice poses serious health and safety risks.
In the bustling industrial hub in Highfield, many welders are using calcium carbide stones directly instead of acetylene gas to cut and repair metal, citing affordability as the main reason.
For many operators, the choice is driven by economic necessity.
“Acetylene gas is too expensive for us. We are doing small jobs. Calcium carbide is cheaper. It allows us to work and feed our families,” said one welder.
Others admitted they were unaware of the long-term health implications.
“To be honest, I did not know about the dangers. Sometimes after work, I feel dizzy, but I thought it was normal because of the smoke,” another welder said.
A third welder acknowledged the risks but said survival leaves little room for alternatives.
“We have no choice. We know it’s not safe, and sometimes these canisters can explode, especially if too much carbide is added. We are just trying to survive.”
Engineer Pedzisai Tapfumneyi, Chief Executive Officer of Verify Engineering, warned against the practice, saying it can have devastating consequences.
“We want to warn the nation to desist from using calcium carbide stones directly because it results in respiratory problems. Most people are using canisters where they put the calcium carbide stones and close those canisters physically. They are using these to cut metals. The system they are using, which is much cheaper for them, is very dangerous. In many cases, it has resulted in explosions,” he said.
He noted that since the commissioning of Verify Engineering’s acetylene plant in Mutare in 2021, local production has helped reduce prices, making safer alternatives more accessible.
Experts say when calcium carbide reacts with water, it produces acetylene gas along with harmful byproducts such as phosphine, which can pose severe health risks.
Long-term exposure has been linked to respiratory illnesses, lung damage and nervous system disorders, while improper handling significantly increases the risk of explosions.
The growing reliance on calcium carbide underscores the urgent need for greater safety awareness, affordable alternatives and stronger support for small-scale manufacturers.
