Southern Research Institute (Southern), under a cooperative agreement with the U.S. Environmental Protection Agency's Environmental Technology Verification (ETV) Program, has conducted a study to evaluate existing sludge gasification technologies, their impacts, and stages of development. Critical components and impacts of these technologies were identified and quantified to assess their development status, potential benefits and drawbacks, and environmental and economic impacts. The study reveals that sludge gasification is a potentially suitable alternative to conventional sludge handling and disposal methods. However, very few commercial operations are in existence. The limited pilot, demonstration or commercial application of gasification technology to sludges, and the unique characteristics of each different technology and site make it difficult to provide an overall assessment of the impacts and economics of the entire technology category at this time. Gasification of sludges and biosolids should be considered an early commercial technology with limited data, and should be evaluated on a site and technology specific basis for potential commercial applications.