A polyethylene plant at Altona has made significant progress towards cleaner production over its 30 year life. The original high pressure plant built in 1961 has been modernised, resulting in improved productivity and reliability and consequently in reduced emissions. The Unipol TM low pressure polyethylene process, which has inherently clean environmental performance, was first introduced in 1972. The gradual shift in production capacity to this process has enabled significant waste reduction and improvements in energy use per unit of production. However, the highlight of the move to cleaner production has been the achievement of zero discharge of wastewater offsite. This has been achieved by water conservation combined with a system of wastewater treatment, recycling and land disposal.