Izmir is a large metropolitan city with a population of 3,114,860. The city consists of 27 townships, each township has a population of not less than 10,000 inhabitants. The two major solid waste disposal sites are in the townships of Uzundere and Harmandali. The amount of solid waste that is disposed at each of these sites is about 800 and 1800 t/day, respectively. In Uzundere, compost is produced from the organic fraction of urban solid wastes while the residual material is deposited at a disposal site with a remaining capacity of 700,000 m(3) as of 2001. Gas monitoring and measurements were carried out at the disposal site in Uzundere. For this purpose, nine sampling wells were drilled on selected locations. Each well was furnished with perforated metal pipes suitable for gas monitoring and measurements. The following gases were monitored: O-2, CH4, CO, CO2, and H2S. The most important finding was that the concentrations of CH4 in the wells ranged from 7 to 57%. Dilution of the CH4 by O-2 down to the LEL levels (5-15%) is always possible and poses a continuing risk at the site. Furthermore, the levels of O-2 require that access to the site be limited to only authorized personnel. (C) 2003 Elsevier Ltd. All rights reserved.