The roll call of damages, caused by reliance on coal, is growing. Coal tar is produced by the part-combustion of fossil fuels as they turn into carbon. Much of it is a by-product of coke manufacture, or gasifying of the raw material. And it’s almost everywhere – used as a sealant for roads, pavements, in playgrounds and on many other surfaces.
Now, the US Geological Survey warns that this gooey, apparently innocuous,  substance contains organic compounds that are not only toxic to aquatic life, but may also cause cancer in humans.
Coal tar has been used on roads for hundreds of years. It was first commercially employed around 1830 in Britain, and later trade-marked as “tarmacadam”.
The UK firm, Tarmac, spread (literally) the substance around the world from the early 20th century, then diversified into aggregates and a range of other construction products. Tarmac was taken over in 1999 by Anglo American, one of the world’s largest mining companies, and sold off last year.