Thomas Midgley's inventions caused his own death, hastened the deaths of millions of people around the world, and very nearly extinguished all life on land. 

Midgley and his employers didn't set out to poison the air with leaded gasoline or wreck the ozone layer with CFCs - but while these dire consequences were unintended... could they have been anticipated?

For a full list of sources used in this episode visit Tim Harford.com