Road Runners

ALTHOUGH TRASH TRAVERSES state lines day in and day out, many states have been concerned about the amount of municipal solid waste (MSW) received from out-of-state sources for disposal since the late 1980s.

Some states have attempted to pass legislation that would regulate waste flows — despite the fact that the states themselves may be sending solid, hazardous, medical or nuclear waste out-of-state for disposal. Federal courts have declared restrictions on interstate waste movement unconstitutional. And Congress has considered, but not enacted, numerous bills that would have provided states with authority to control interstate and international waste shipments.

Nevertheless, according to a recent report by the Washington, D.C.-based National Solid Wastes Management Association (NSWMA), summarizing 2001 data collected by the Congressional Research Service (CRS) and selected states, MSW imports have nearly tripled in the past 12 years.

National Trends

Nearly all states import and export MSW; many ship waste back and forth at different points along a common border. MSW import and export data generally follow similar trends. According to CRS, about 12.6 million tons of MSW were exported in 1989, while 10.8 million tons were imported. In 2001, exports rose to more than 34.5 million tons, a 174 percent increase from 1989 rates. Imports rose to more than 35.1 million tons, a 225 percent increase from 1989 figures. On average, about 9 percent of the MSW generated in the United States was exported to another state for disposal or management in 2001. [See “Interstate Shipments of Municipal Solid Waste” on page 41.]

State Trends

There was an intricate web of interstate waste movements in 2001 between states and across U.S. borders with Canada and Mexico. In fact, there were 205 waste interactions, where an interaction is the movement of MSW between two states or countries as an import or export. This represents a 52 percent increase over the 135 interactions recorded in 2000.

Of the 205, 147 interactions or 72 percent were between neighboring states. Ninety-eight transactions, or 48 percent, were paired interactions in which MSW moved as both an import and export between the same two neighboring states. Transactions occurred primarily in the Northeast, Mid-Atlantic and Midwest, where landfill space generally is limited.


As waste volumes have increased over the years, so have the number of waste exporting states. In 1989, only 13 states and the District of Columbia exported waste for disposal or management. By 2001, exporting states had grown to 49 plus the District of Columbia, two Canadian provinces (Ontario and British Columbia), Mexico, Antarctica and the Virgin Islands. The District of Columbia and New Jersey exported more than 50 percent of the MSW they generated, and Maryland exported almost 47 percent.

The NSWMA believes that the high export rates may be attributable to the lack of disposal capacity within states' jurisdictions. All other states had export rates of less than 30 percent of their generation rates. Fourteen states exported between 10 and 30 percent of the MSW they generated. The remaining exporting states (34 states), which represents the majority, exported less than or equal to 10 percent of the MSW that they generated. Notably:

  • Six states (Illinois, Maryland, Massachusetts, Missouri, New Jersey and New York) and Ontario exported more than 1 million tons of MSW. The number of states exporting more than 1 million tons of MSW per year declined in 2001 compared to 2000 when eight states (California, Illinois, Maryland, Missouri, New Jersey, New York, North Carolina and Ohio) exported that amount.

  • The state exporting the largest volume of MSW in 2001 was New York (7.49 million tons), followed by New Jersey (5.43 million tons).

  • Twenty states (Alaska, Arizona, Arkansas, Colorado, Delaware, Kansas, Maine, Mississippi, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Virginia and Wyoming) exported fewer than 100,000 tons.

  • Hawaii was the only state that did not export MSW for disposal.


In 1989, 14 states imported waste. By 2001, 45 states were importing MSW. The largest MSW importer was Pennsylvania (10.67 million tons) followed by Virginia (4.1 million tons) and then Michigan (3.6 million tons).

Pennsylvania also had the largest amount of imported waste compared to waste generated. Pennsylvania's imports represented 76 percent of the waste it generated in 2001. Seven states had import rates greater than 20 percent when compared to generation rates, including Virginia, Oregon, Kansas, Indiana, Wisconsin, New Mexico and Michigan. Eight states (Iowa, Kentucky, Mississippi, Nevada, New Hampshire, North Dakota, Ohio and West Virginia) imported between 10 and 20 percent of the waste they generated. The remaining 36 states imported less than 10 percent of the waste they generated.

  • Eight states, including Illinois, Indiana, Michigan, Ohio, Oregon, Pennsylvania, Virginia and Wisconsin, imported more than 1 million tons of MSW in 2001. In 1989, only Illinois, Indiana, Ohio and Pennsylvania imported more than 1 million tons.

  • Six states (Alaska, Delaware, Florida, Hawaii, Minnesota and Vermont) did not import MSW.

Net Imports and Exports

The majority of the states (27) had net imports or exports fewer than 500,000 tons in 2001. Ten states had net imports or exports less than 100,000 tons including Alaska, Arkansas, Colorado, Delaware, Hawaii, Montana, North Dakota, South Dakota, Tennessee and Utah. New York was the largest net exporter at 6.65 million tons, followed by New Jersey at 4.54 million tons, Maryland at 2.04 million tons, Missouri at 1.49 million tons, Illinois at 1.64 million tons and Ontario at 1.98 million tons.

Five states and Ontario had net imports greater than 1 million tons. Pennsylvania was the largest net importer at 10.09 million tons followed by Virginia at 4.05 million tons, Michigan at 3.45 million tons, Oregon at 1.28 million tons and Ohio at about 1 million tons.

Interstate waste movements represent routine partnerships among states and municipalities, based on economic, social, environmental and political factors. The NSWMA believes that the amount of MSW moving interstate will increase in the future. Additionally, the total amount of waste moving interstate and the number of states exporting or importing MSW probably is greater than the numbers reported in 2001 because states vary in how they collect data about interstate waste shipments.

The figures on interstate MSW flows were based on CRS data and information provided by states. Because of congressional interest in interstate waste shipments, Congress, in 1990, requested that CRS determine the amount of MSW moving between states and internationally. For a copy of the most recent report published in November 2002, e-mail Ed Repa, NSWMA director of environmental programs, at: [email protected].

Ed Repa is the director of environmental programs for the National Solid Wastes Management Association, Washington, D.C.