An integrated chemical production complex provides a rich environment for the application of enterprise-wide optimization techniques. A world scale site can be composed of dozens of production plants manufacturing hundreds of products. This paper discusses the nature of an integrated chemical production site to identify the opportunities for enterprise-wide optimization. It shows how the site is composed of sub-systems, called envelopes, which involve the production of a basic chemical and its downstream derivatives or comprise a network of units that provide an important utility. Several planning and operational challenges in these envelopes are shown to be excellent optimization opportunities. The challenge of waste disposal scheduling is presented in detail along with a solution using a resource task network. (C) 2009 Elsevier Ltd. All rights reserved.