Where to find the answer: See Sen. Patrick Leahy's Mercury Primer.

1b. How are most people in the United States exposed to mercury? By breathing mercury-laden air? By drinking water contaminated with mercury? By ingesting it? Given this exposure pathway, explain why it is sensible to regulate mercury under the Clean Air Act.

Partial answer: Even though most human mercury exposure comes from ingestion, much of our control efforts have focussed on reducing airborne mercury pollution. To explain why this is sensible, trace the path that starts with mercury emission into the air and ends with human exposure to this mercury.

1c. Explain how the source you identified in question 1a above is regulated under the Clean Air Act Amendments of 1990. At present, is there a final rule regulating mercury under either section 111 or 112 of the Clean Air Act? If so, briefly explain what this rule does, and its statutory basis, and the date (year) when mercury was first regulated under section 111 or 112. (one or two paragraph answer)

Answer hint: See "Controlling Power Plant Emissions: Decision Process and Chronology" in the Required Course Pack, as well as the March 2005 Clean Air Mercury Rule and class discussion thereof. Also note that in March 2005, EPA withdrew their previous decision to list mercury as a HAP under section 112.

2. Summarize the history of major efforts by the Environmental Protection Agency to regulate mercury emissions from incinerators, chlor-alkai plants, and coal-fired power plants. Start with the Clean Air Act amendments of 1990, and continue throught the final Clean Air Mercury Rule of 15 March 2005. (2 or 3 paragraph answer)

Where to find the answer: See Heinzerling and Steinzor (34 ELR 10297) in the Required Course Pack, the Clean Air Mercury Rule, and your notes from Kevin Leske's class. Sen. Leahy's mercury timeline summarizes the answer to this question, and much more.