The smelting industry needs to promote the availability of dust masks of more than one size, according to the research scientists behind a recent working environment study at Norwegian smelting plants.
In a recent major multidisciplinary research project, dust masks used in the Norwegian smelting industry have been subjected to comprehensive testing. Solveig Føreland, a toxicologist and occupational hygienist at St. Olav’s Hospital in Trondheim, was responsible for the trials. She points out that masks are usually made only in one size, and are designed to fit users with relatively large faces.
Knowledge-Building Project for Industry (KPN) with funding from The Research Council of Norway via the Nano2021 program.
Duration: From June 2015 to June 2019
Industy Partners: The Norwegian Ferroalloy Producers Research Assoiation (FFF), Washington Mills and Saint-Gobain.
Research partners: SINTEF (project manager), University Hospital of North Norway (UNN), St. Olavs Hospital, The National Institute of Occupational Health (STAMI) and Norwegian University of Science and Technology (NTNU)
Hazardous ultra-fine dust
The testing is part of DeMaskUs, an interdisciplinary research project for which the smelting industry in Norway has taken the initiative. The purpose of the project is to ensure the best possible working environment in Norwegian silicon, ferroalloy and silicon carbide plants – the industries that provide us with materials for the manufacture of everything from solar cells and axe heads, to advanced electronic equipment.
When liquid metal is tapped from smelting furnaces, the temperature reaches more than a thousand degrees Celsius. To an onlooker, the glowing metal, smoke and sparks from metal production may be reminiscent of a volcanic eruption.
Fortunately, it’s not as dramatic as it might appear. The activities in a smelting plant are strictly controlled and carefully planned, and employees are padded from head to toe for protection. However, at the interface between metal and air there is an unwanted and almost invisible by-product: ultra-fine dust.
“When the temperature is as high as it is in a smelting furnace, a number of chemical reactions come into play. Amongst other things, the molten metal reacts with oxygen from the air in the smelting hall. The product of the reaction is a fine oxide dust. The smallest of these particles are almost invisible, and the industry doesn’t want its employees to be inhaling this dust”, says Ida Teresia Kero, a SINTEF research scientist.
Inhalation causes illness
Kero holds a key role in the DeMaskUs project, in which several industrial companies are collaborating to research the dust issue. She is the leader of an interdisciplinary team of research scientists from the University Hospital of North Norway (UNN), St. Olav’s Hospital, the National Institute of Occupational Health (STAMI), the Norwegian University of Science and Technology (NTNU) and SINTEF.
Testing and trials of dust masks are included because a number of studies have shown a connection between inhalation of industrial dust and disorders of the airways and lungs. Occupational hygienist Føreland explains:
“Experience shows that the incidence of COPD, to some extent, can be linked to the working environment, and that employees working at smelting plants and other industries where they are exposed to dust have an increased risk of developing lung disorders. In the DeMaskUs project, we also want to study how dust generated during activities such as the tapping of smelting furnaces may contribute to adverse health effects”.
Partial protection is better than none
The University Hospital of North Norway and St. Olav’s Hospital have tested how effectively the existing dust masks protect against dust. Over a hundred test subjects, both male and female, who work every day near large, scorching furnaces, were invited to test a total of a dozen different dust masks.
First, the subjects carried out various exercises while wearing a mask and walking on a treadmill in an office environment.
“These tests demonstrated that, provided they fitted the user’s face, the dust masks captured even the smallest particles”, says Føreland.
However, testing in an office environment is one thing. The scientists wanted to put the masks through their paces by testing them in the dustiest areas close to furnaces.
“The masks provide good protection if you are in “friendly” surroundings with a brand-new mask, and if you are also a clean-shaven man. However, a pilot trial carried out in an industrial furnace hall showed that the masks didn’t necessarily provide as effective protection there. However, this must not lead us to believe that we can do without a mask when working near a furnace. Partial protection is of course far better than none”, says Føreland.
In the pilot trial the scientists encountered problems with the measuring equipment, which did not react well to the heat and dust in the furnace hall. They therefore set out to acquire more advanced measuring equipment and are currently developing a method for determining whether the degree of protection of the masks is impaired in the conditions prevailing near a furnace.
Why some people leave the mask behind
Although most smelting plant employees know that they should use protection, there are a number of psychological aspects that get in the way. Øystein Robertsen, a psychology research fellow at UNN has studied this in detail. The operators themselves state that condense on the protective goggles, itching and heat are among the most common reasons why the dust masks aren’t always worn.
“There are many indications that users are often more influenced by the unpleasantness of wearing a dust mask than by the risk of developing COPD or other lung disorders. Health problems are a result of exposure over a prolonged period, just like the risks involved in smoking, and we have a tendency to play down potential risks that lead to problems later. We often lose focus if the consequences are not acute”, says Robertsen.