The upside of using lead in paint is that it bestows a pleasing finish: colourful and durable. The downside is that application and removal generates dust that, in small quantities, ends up in people’s mouths. Once ingested, the lead atoms have a nasty propensity for being mistaken by the body for the non-poisonous metals it uses in day-to-day chemical processes. This leads to a dizzying array of health problems, among which are cognitive impairment, particularly in children; adults become likelier to contract kidney and heart problems, both of which can be fatal. Not so pleasing a finish, after all.
Britain nearly stamped out fatal lead exposure in the second half of the 20th century, but much of the world has yet to catch up. Some countries have laws that proscribe lead paint, but they are not always enforced. As a result, across the world, 815m children have high levels of lead in their blood and 900,000 people are killed by it each year.