Hazardous wastes may be transported to be treated, stored, or disposed of. Facilities that generate hazardous waste are required to prepare a shipping document, or “manifest,” to accompany the waste as it is transported from the site of generation. This manifest must accompany the waste until its ﬁnal destination and is used to track the wastes from cradle-to-grave.
The potential for pollution releases during the transportation of waste varies; the more hazardous the waste and the larger the volume that is transported, the more devastating the environmental/human health impact if an accident occurs. Trafﬁc accidents or train wrecks can result in waste spills and releases of pollutants that may contaminate the air, water, and soil. Wastes may also be released while being loaded or unloaded during transportation.
Approximately four billion tons of regulated hazardous materials are shipped within the United States each year with more 250,000 shipments entering the U.S. transportation system daily. The Emergency Response Notiﬁcation System (ERNS) database of the Environmental Protection Agency (EPA) shows that from 1988 to 1992 an average of nineteen transportation accidents involving toxic chemicals occurred each day.
The U.S. Department of Transportation (DOT) requires that placards identifying the type of hazardous material being transported be placed on the outside of any vehicle transporting hazardous materials or wastes. Placards are used to determine potential hazards in the event of a spill and are placed on all four sides of a vehicle so that HAZMAT teams, ﬁre, emergency, medical, and other personnel who respond to accidents may quickly identify the contents and associated hazards. Placards are required if one thousand pounds or more of a hazardous material is transported and if any amount of material classiﬁed as explosive, poisonous, radioactive, or a ﬂammable solid is transported.
The DOT classiﬁes materials based on nine hazard classes represented by symbols. The classes are explosives, gases, ﬂammable liquids, ﬂammable solids, oxidizers, poisonous materials, biohazards, radioactive materials, corrosives, or other regulated materials.
The routes that transporters of hazardous waste use must be carefully considered to minimize the risk of an accidental release. If possible, densely populated areas should be avoided. The type of highway or road and the weather conditions along the route must also be considered. Risk analysis may become important in selecting routes for hazardous waste transport in order to minimize adverse impacts to human health in case of an accidental release.
Due to rapidly decreasing space in urban landﬁlls, ofﬁcials have been forced to ﬁnd alternate locations for municipal waste disposal. This has created signiﬁcant ﬁnancial incentives for rural communities to accept garbage from urban areas. Depending on the location of these rural facilities, it may be necessary to transport large quantities of wastes by a variety of methods, most often by truck, railway, or barge.
Many citizens are concerned about the transportation of the waste through their communities and the risks involved. People are also concerned that the municipal waste from urban areas may be contaminated with toxic chemicals or substances that could contaminate local drinking water supplies.
Disposal of hazardous wastes in the United States can cost up to $2,500 per ton. This has led to the practice of selling waste to developing countries for disposal at a much lower cost. This international waste trade may be illegal in some instances, but the hefty sum paid to those who accept the wastes remains tempting to developing countries.
However, the actual composition of the wastes received by developing countries is often misrepresented by those selling the waste. In addition, most developing countries lack the resources and technical expertise to safely manage these hazardous wastes.
Trade in hazardous wastes is a global issue. About ten percent of all hazardous wastes generated around the world cross international boundaries. A large portion goes from industrialized countries to developing countries where disposal costs are lower.
Although developing countries may lack the ﬁnancial and technical capacities to clean up hazardous waste releases in their countries, these countries nevertheless are sites for treatment, recycling, and disposal of wastes from abroad.
The Basel Convention on the Control of the Transboundary Movement of Hazardous Wastes and Their Disposal is the ﬁrst global environmental treaty to control the international trade of waste. Under the Convention, trade in hazardous wastes cannot take place without the consent of the importing country and cannot occur under conditions that are assessed as not environmentally sound.
As of April 2002, 150 countries had ratiﬁed the convention. A new protocol adopted by the convention in 2000 provides the ﬁrst international framework establishing liability for damages that may result from the transportation or disposal of hazardous wastes across foreign borders