The problem with lead is that it tends to bio-accumulate in various types of body tissue, making blood lead levels hard to bring down. Chronic exposure builds u

The problem with lead is that it tends to bio-accumulate in various types of body tissue, making blood lead levels hard to bring down. Chronic exposure builds up over time. I also disagree that 483 tons is "a very small amount of pollution". Lead cannot be compared with more typical pollutants like CO2. A better comparison might be mercury, which measured 52 tons emitted in 2011. I still won't say 52 tons is small, but it's a lot better than 483! I want to reiterate that small propeller planes that seat 2-6 people make up virtually the entire market for leaded aviation fuel. Larger propeller planes typically have turboprop engines which burn kerosene like most jet/commercial aircraft. There is a big cost upon society caused by a small number of people, for something that is completely unnecessary (private air travel).