By Alice Kiingi
MOSES Mayengo, 28, has been a welder for 11 years. He works at Nakawa, a city suburb. His overall is stained with black oils. He has dark goggles through which he looks directly into the strong light from his welding that produces sparks of metallic particles that make fireworks patterns.
“I was inspired by my first employer who taught me how to cut, melt, join and bend metals into a designed product,” Mayengo says.
He knows the work is a health hazard but says he cannot afford the required protective gear.
Mayengo only uses ordinary sun goggles and, occasionally, a black mask with a glass protection as he welds.
According to the Documentation of the Threshold Limit Values and Biological Exposure Indices Ed 6, welding is the process of joining metal surfaces by heating them until they are slightly molten, then hammering them together to form a single piece of metal. In Uganda, the common ones are gas welding, where heat is generated by a combination of oxygen and fuel gas and electric welding where electrodes are used.
“Those sparks can leave small burns. Even the light has a way it pulls the skin to make it rough. The smoke itches and chokes, sometimes making you cough,” Mayengo says.
Dr Friday Agaba, an environmental occupational health specialist in the ministry of health, says welding fumes have dangerous chemical components like oxides of nitrogen and sulphur, carbon oxide and volatile organic hydrocarbons.
“Exposure to welding fumes through inhalation or eye contact may cause long-term health problems depending on the metal being welded and the methods being used,” says Agaba. He says respiratory effects include coughing, wheezing, bronchitis and heart diseases.
Dr. Tahobari Babigamba, an Ear, Nose and Throat specialist at Kim Medical Centre, says inhalation of the fumes can result in such respiratory problems like asthma and bronchitis.
“When the fumes reach the lungs, they are absorbed into the blood system and may cause cell mutation (change of cell shape as a result of fast division of cells), affecting organs like the kidney, liver and the bone marrow,” he says.
Babigamba says the changed abnormal cells replace normal ones which cease to function well and divide at a high rate, resulting into diseases like liver cancer, Nephroma (kidney) and Leukaemia (bone marrow). The document referred to metal fume fever, a condition that resembles influenza and is characterised by fever, eye, nose and throat irritation, chills, headaches, nausea, muscle pain, shortness of breath and a metallic taste in the mouth.
Evaristo Byekwaso, NEMA’s environmental audit and monitoring officer, says the authority considers a gas to be hazardous if it exhibits corosity (wearing out the walls of a building), toxity (poisonous) and reactivity (causing harmful effect to people and vegetation).
“When gases like sulphur and nitrogen dioxide react with water, they form acid solutions that damage vegetation, wear out buildings, irritate the eyes and interfere with the respiratory system,” he says. Dr. Mustafa Kanji, a consultant with City Optics and Contact Lens Centre, says intense exposure of the free-flowing ultra violet light damages the conjunctiva and the retina of the eye, turning it red and partial or total blindness eventually.
There are welding accidents, too.
Sande Ezra, a welder in Kampala, collapsed when his gas tubes leaked. It could have been worse because tubes not well fitted can explode the gas cylinder.
Mayengo says his colleague Isaac Mitala was shocked by electricity and died instantly. “some get electric shocks, burns especially in a wet environment, when using exposed or wrong wires like telephone cables and poorly insulated welding machines.”
What can be done?
According to Agaba, these health dangers are worsened by poorly ventilated rooms, inexperienced and untrained workers and those who smoke, eat or drink in areas where welding fumes are generated.
Kanji says welders need big ultra-violet protection goggles to protect the bare eyes in all angles from the metallic sparks.
Welders should use appropriate protective equipment and clothing, including welding gloves to prevent burns and breathing masks to prevent inhalation of gases.
Chemical safety goggles or face shields should be worn during any operation in which intense light or a toxic substance may be splashed into the eyes.
Chemical-resistant clothing like aprons or overalls is useful in preventing skin contact.
Kanji calls on the ministries of health and labour to put in place relevant occupational health and safety laws and ensure they are enforced through awareness programmes for the workers and employers.
Health workers should also be trained in early detection of adverse health effects.