So, in 1974 the Environmental Protection Agency developed guidelines for eventually eliminating leaded gasoline.

所以在 1974 年，美国环保局发布了一份计划完全取缔含铅汽油的指导文件。

It wasn't easy, other additives had to be developed for cars that had been designed to run on leaded gasoline, many of which had their own problems.

这并不容易，汽油公司要开发出新的添加剂，以用于原本设计成使用含铅汽油的汽车，更别提很多无铅添加剂还有自身的问题。

But 1996, the last leaded gasoline was sold in the United States and most gas stations still use labels to assure everyone that even their cheapest fuel, is unleaded.

但是在 1996 年，美国终于卖完了最后的含铅汽油，而现在大部分加油站依然贴上标签让人知道就算是他们最便宜的汽油都是无铅的。