Until recently, methyl tert-butyl ether was used as an additive in gasoline. We call it MTBE for short, and it helped make automobile exhaust cleaner. But there was a problem. As you may know, gasoline is often stored in huge tanks underground. When you're filling up at the gas station you're most likely parked right above a huge underground tank. In a perfect world, these tanks would never leak and no gasoline would ever seep out of them. But as some of you may have figured out, this world is far from perfect, and sometimes gasoline leaks out of these tanks and seeps into the groundwater. This was especially a problem in California, and in some parts of the state unusually high levels of MTBE were showing up in drinking water. While MTBE was great for keeping car exhaust clean, but it wasn't the sort of thing you'd want to drink. The use of MTBE became very controversial.

The long and short of the matter is that in 2000, the U.S. government banned adding MTBE to gasoline. This was a controversial move. The case pitted our need for clean air against our need for clean drinking water. In this activity you and a partner are going to research this case and draw your own conclusions. Was the government right or wrong to ban MTBE from use in gasoline? That's the question you're going to be exploring.

As a team of two, one of you will research MTBE and what its benefits are. Write a 1-2 page report, and be sure to answer the following questions:

1. What kinds of compounds are the major components of gasoline?

2. If the gasoline burns completely in an automobile engine, what would the products of the reaction be? That is, what would the exhaust of the car be?

3. What kinds of reaction products are produced when gasoline does not burn completely?

4. Which of these compounds can be partially eliminated from automobile exhaust by adding MTBE to gasoline?

5. Consider the compounds that MTBE partially eliminates from automobile exhaust. What kinds of health problems can these compounds cause if they are released into the air?

The other team member will research the risks of using MTBE. Write a 1-2 page report, and be sure to answer the following questions:

1. How is MTBE detected in drinking water? How is the concentration of MTBE measured?

2. What is the EPA concentration limit for MTBE in drinking water?

3. What concentrations of MTBE have been found in drinking water in California?

4. What kinds of health problems can be caused by drinking water contaminated with MTBE?

5. What were the incidences of MTBE-related health problems in areas with the highest MTBE concentration in drinking water?