21 April 2014 - BBC News - Did removing lead from petrol spark a decline in crime?

Working away in his laboratory in 1921, Thomas Midgley wanted to fuel a brighter tomorrow. He created tetraethyl lead - a compound that would make car engines more efficient than ever.

But did the lead that we added to our petrol do something so much worse? Was it the cause of a decades-long crime wave that is only now abating as the poisonous element is removed from our environment?

If you want to understand the causes of crime - and be tough on them - you need to start with lead, says Dr Bernard Gesch, a physiologist at Oxford University who has studied the effect of diet and other environmental factors on criminals.