Artificial reefs are widely considered to benefit the marine environment and enhance fishing for the recreational angler. In the past, private fishing clubs and local governments were able to build small reefs with donated materials and manpower. In general, though, the expense of transporting and handling even donated material has become a major obstacle to future reef construction. Yet, due to the large number of recreational fishermen, economic benefits can be realized in the local communities near the fishing sites. The increase in the utilization of coal combustion for generating electricity has resulted in large volumes of wastes requiring safe disposal. Landfilling practices are undesirable in urban coastal areas or in areas with shallow ground water tables. Stabilization of these wastes into hard blocks could allow safe ocean disposal and create artificial reefs at no cost to the taxpayer. 500 tons of fly ash and flue gas desulfurization (FGD) sludge were formed into 15,000 blocks (

cm) and placed in the Atlantic Ocean as an artificial reef. Five years of laboratory and field investigations have been conducted to determine the environmental acceptability of this material in the sea. The blocks are found to support a wide diversity of organisms on the surfaces as well as a fish population comparable to an existing reef nearby. No adverse effects have been detected to the marine environment and the blocks continue to retain their structural integrity.