Factories and pollution go hand in hand. As steel industries sprang across the world, the level of pollution in the air began to rise. With no research and debate about health issues due to air pollution, it was important to devise new methods to manufacture steel and to keep the pollution in check.

Stainless steel across the world was manufactured at mini-mills, which melted scrap steel to make the metal goods. Mini-mills had electric arc furnaces, which were also invented by William Siemens. Electric arc furnaces used carbon electrodes to melt scrap steel via electric charges. The recycling of old steel in mini-mills was the first step towards sustainable smelting, but there was still a long way to go. Steelmaking produces a lot of greenhouse gases; the still-prevalent basic oxygen process, a method devised over a hundred years ago, involves the burning of coal, which produces four times more carbon dioxide than electric furnaces. However, electric furnaces are not the final solution, as there is a limited of scrap steel that can be recycled.

Metallurgists around the world are brainstorming ways to invent eco-friendly steel manufacturing processes. Researchers at MIT are experimenting with new electricity-based technologies to smelt metals. These technologies can hugely reduce greenhouse gas pollution, if they are bettered to work on iron and steel, which are metals that have high melting points. Techniques that are used to reduce vehicular emissions are being experimented with as well. Voestalpine, an Austrian manufacturer, began constructing a mill that will use hydrogen instead of coal, so as to reduce emissions. Further East, the Chinese government put a cap on the total steel output for the year 2017.

The journey to make the perfect steel has been an ongoing one, right from the Indian crucibles, to the German blast furnaces, to the American steel plants. Each breakthrough and invention has moved towards a better-than-previous steel, yet the iterations never stop. The burning question still burns in the 21st century: how to improve the process of making steel?