Back in the 1970s, few welders or employers gave much thought to the risks associated with breathing in fumes and gases. But at its labs on Lidingö, outside Stockholm, Linde Europe North (then still called AGA) was already working to reduce them.

"There was a little group of people who realised that there was a problem with ozone: It was described in the literature, but it was not a big issue in the market," explains Per Bengtsson, a senior applications specialist at Linde, who began working at the labs in 1987.

"They decided that if we could develop something to put into the shielding gas that took away the ozone directly in the arc, it would be a good product to have on the market: just to protect the welders, to help them have a better life."

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Repeated exposure to ozone brings long-term risks. It is classed as carcinogenic in the German Technical Rules for Hazardous Substances (TRGS 905) and the European Environment Agency (EEA) claims that it can cause permanent lung damage, setting the maximum permissible level of ozone in air inhaled during a working day to just 0.00001%.

In 2018, the International Agency for Research on Cancer (IARC)changed the classification of welding from "possibly carcinogenic to humans" to "carcinogenic to humans".

According to several work environment authorities, welding fumes are among the most common reason given for respiratory diseases in the metal and machine industry.

But thanks to MISON’s unique NO-blend, welders who use the gas are spared many of the risks associated with ozone exposure.

Studies show that MAG welding carbon steel with MISON produces between a quarter and a tenth as much ozone as a standard shielding gas. When TIG-welding stainless steel with MISON, ozone is reduced to a fifth.

Furthermore, the nitrogen oxides generated when using MISON as a shielding gas is between 5 to 20 times less harmful than the ozone it replaces.

The use of the gas started to take off in 1985 when Linde Europe North (then called AGA) followed up the original product, MISON Ar – which is used for TIG welding of all materials except titanium – with MISON 20, which is used for MAG welding on mild steel.

It gained still greater momentum when it became recognised that using MISON for MIG/TIG welding of aluminium stabilized the arc which gave a cleaner weld, with deeper penetration.

According to Jessika Wikström, a former welding coordinator who now works as a Linde welding specialist, MISON has become synonymous with shielding gas among many welders.

"I started welding right after school, and the first time I got familiar with shielding gases they were just called 'MISON'," she recalls.

And when employees have a say, they often demand MISON.

"Everyone who has worked as a welder knows that there are sometimes a lot of fumes and that it's not always the best environment, so I think it's a no-brainer," she says.

It's really a core product that’s valued highly by our customers,” says Bengtsson. 

One customer even built MISON into a new labour agreement that mandated improvements for workers every year. As part of the deal, the company shifted to MISON.

When another customer, who had nitrogen oxide mixed into the company’s shielding gas on site, switched it off, the employees began complaining.

"They couldn't really put their finger on what it was, but they felt in their throat, that there was a difference," Bengtsson remembers.

MISON can also improve the bottom line for companies, reducing the number of sick days and use of less skilled temp workers, while boosting morale and productivity.

According to Wikström, a better working environment is also key to attracting younger employees. 

"I think that's one of the big things we need to focus on to attract young people, because I don't think they are going to put up with standing in fumes if it might be toxic for them in the long-term," she explains.

For Bengtsson, who has been working with MISON for three of its four decades, the 40th anniversary is an opportunity to take stock.

"It's something that we are quite proud of – that we were the only gas company to make such a product in the service of the welder," he says.

"And hopefully, it will still be making an important contribution to their working environment in 40 years to come."