Trade liberalization and global pollution

Proponents of trade liberalization argue that freer trade might actually improve the quality of the environment. For example, the international environmental policy of the U.S. and other industrial nations is based on the "polluter-pays principle." This approach is intended to give producers the incentive to develop more pollution-control techniques. I need an examples and information, views, comments that support thae statement that rade liberazation will create global polution.

Examples, case studies, articles, policies are all welcome, just point me in the right direction.