legislation was rejected by the Senate on Tuesday, March 26, 2019, with Senate Majority Leader Mitch McConnell (R-KY) leading the voting process. The legislation received 57 "no's" and 43 "presents". Issues Since the environmental movement of the 1970s, the nature of environmental issues has changed. While the initial emphasis was on conventional air and water pollutants, which were the most obvious and easily measurable problems, newer issues are long-term problems that are not easily discernible and can be surrounded by controversy. Acid deposition Acid deposition, in the form of acid rain and dry deposition, is the result of sulfur and nitrogen dioxide being emitted into the air, traveling and landing in a different place, and changing the acidity of the water or land on which the chemicals fall. Acid deposition in the Northeast United States from the burning of coal and in the West United States from utilities and motor vehicles caused a number of problems, and was partially exacerbated by the Clean Air Act, which forced coal power plants to use taller smoke stacks, resulting in farther transmission of sulfur dioxide in the air. During the Carter administration, the United States undertook a risk-averse policy, acting through the EPA and Council on Environmental Quality (CEQ) to research and control the pollutants suspected to cause acid deposition even in the face of scientific uncertainty. The Reagan administration was more risk tolerant. It argued that, given the scientific uncertainties about harm and exposure levels, new expenditures should not be undertaken that would curtail energy security and economic growth. During George H. W. Bush's presidential campaign, he called for new Clean Air Act legislation to curtail sulfur- and nitrogen-dioxide emissions. In 1990, after he was elected, amendments to the Clean Air Act were finally passed that cut emissions by over 12 million tons per year, set up a market-like system of emissions trading, and set a cap on emissions for the year 2000. These goals were achieved to some degree by the installation of industrial scrubbers. While the initial costs in cutting emissions levels were expected to be over $4.6 billion for utilities and a 40% rise in electricity costs, the impact ended up being only about $1 billion and a 2–4% rise in electricity costs. Part of the reason for the relatively low costs is the availability of low-sulfur coal. Ozone depletion Ozone depletion is the reduced concentration of ozone in