If you were around at the end of 1995, you were here when U.S. gas stations sold their last gallon of leaded gas.

From the 1920s to the 1970s, almost all cars were built to burn leaded gasoline. If you burned gasoline without the lead additive, your engine would knock and eventually break and have to be replaced.

The downside of leaded gas was that it added lead to car exhaust.  With lots of cars driving around cities, inner-city children breathed a lot of lead.  That lead lowered their average I.Q. by about 3 points and increased their chances of ADHD, depression, anxiety and neuroticism.  Three I.Q. points is not a super big deal.  On average, three I.Q. points is associated with about 40 points off your combined 1,600-point SAT scale.  If you were going to get an 800 combined score, with lead, you would get more like 760.  Similarly, people who grew up breathing leaded car exhaust are, on average, only a bit more likely to be depressed, have ADHD, or a neurotic personality disorder. But if you were someone who would have been close to troubled, the addition of lead might be what pushed you over.

Leaded gas was phased out in different years in different places, allowing for a measurement of the impact of leaded gas that is separate from other things going on. The current estimate is that leaded gas doubled the number of homicides and other crimes in the U.S. from 1970 to 1990. (Did you know we had a huge drop in violent crime after 1990?)

Children growing up on farms who helped out near tractors and trucks also breathed a lot of lead fumes. Anyone with memories of diesel exhaust from before 1996 got a face full of lead, along with the nitrogen oxides, aldehydes and sulfates that are still in diesel exhaust.  Same goes for kids who rode in diesel school buses.

In 1970, every car on the road burned leaded gasoline when the Environmental Protection Agency banned making any more cars or trucks that released the kind of pollutants cars had previously released. That led to the invention of the catalytic converter. Every 1975 model year vehicle had a catalytic converter and could not burn leaded gas. Catalytic converters have been in cars and trucks from then on. To serve the new cars, gas stations started providing unleaded gasoline next to their leaded gas pumps.

I grew up expecting that every gas station had both an unleaded and a leaded gas option.  In researching how we got away from leaded gas, I found that the federal government banned leaded gas altogether at the end of 1995. It’s been almost 30 years, and I never noticed that the leaded pumps were gone. I guess no one mentioned to me they were taking the leaded gas away. Certainly, I never cared, because by 1996, only hobbyists had cars that required leaded gasoline, and most hobbyists had had their engines rebuilt to burn unleaded gas.

What happened? Where did all the lead-gas cars go? In the 21 years between 1975 and 1996, the lead-gas cars wore out and were junked.

We now have almost 300 million gasoline cars and trucks in the United States. Those gasoline vehicles are releasing the carbon dioxide that is causing global warming. You might ask “How will we ever replace all those cars and trucks?” The answer is “the same way we replaced leaded-gas cars and trucks” We’ll stop building new gas vehicles and about 25 years later, only hobbyists will still have gasoline-powered cars.

So far, there is no federal law like the 1970s law banning the kinds of pollution you get from lead-gas cars. New Mexico has banned new gas cars after 2025. Washington state, Maine and Oregon have banned them after 2030.  California, Connecticut, Hawaii, Massachusetts, New Jersey, New York, North Carolina, Rhode Island and Vermont have banned new gas vehicles after 2035.

By the time we get to those deadlines, it might not matter much. Here in Washington state, 20% of new cars and trucks are electric, up 100% since 2021. If the current trends continue, most people won’t want new gas cars anyway by the time they are banned.

Nationally, we’re only up to 9% of new vehicle purchases being electric. The rest of the country might need those extra five years to 2035 to catch up to those of us in Washington state.

Why wait?

When you buy a new gas car, you are committing people to burning about 8,000 gallons of gasoline. Your new car will probably burn about one gallon of gasoline for every 30 miles it runs, and it will probably go about 250,000 miles. Not necessarily driven by you. If you sell your car after 50,000 miles, someone else will buy it as a used car. It may go through a series of used-car buyers, each paying less and less. Eventually, it will be exported to some place like Africa or South America, where talented mechanics who are paid very little will nurse it along to 250,000 or 300,000 miles, before they give up on it.

In contrast, you could buy or lease an electric car or truck. That prompts manufacturers to make another electric vehicle, avoiding those 8,000 gallons that would have been burned for a new gas car or truck. To have the biggest impact on gasoline burning, you could commit to leasing a new electric vehicle every three years. Each time you started a new lease, you would be launching another electric vehicle into the world to displace a gas car or truck.