A group of senators encouraged U.S. Trade Representative Ron Kirk in a letter Wednesday to ensure that negotiators remain firm on demanding a legally binding environment chapter in any agreement that arises out of free trade agreement talks among Pacific Rim nations.

The senators, led by Oregon Democrat Ron Wyden, said the bipartisan consensus reached May 10, 2007 among members of Congress and the Bush administration, on language aimed at preventing the derogation of a nation’s environmental laws in the name of trade opportunities, should serve as the framework in discussions surrounding the Trans-Pacific Partnership, or TPP.

“A binding and enforceable TPP environment chapter that stands up for American interests is critical to our support of the TPP,” they said in the letter. Olympia J. Snowe of Maine was the lone GOP co-signer. Democrats pushed for the inclusion of enforceable environmental and labor standards in pending trade deals before Congress votes on them after they won control of both chambers in the 2006 elections. Trade pacts approved since then with Peru, Panama, Colombia and South Korea all contain provisions directing the enforcement of multilateral environmental agreements that have a clear link to trade, as well as the application of dispute resolution options that have been made available in commercial cases to environmental issues.

Strong environmental protections built into free trade agreements is crucial in combatting illegal logging and other threats to natural resources, the senators said, such as overfishing spurred by generous subsidies in other countries.

Observers say other participating nations have been lukewarm to the idea, with none publicly favoring a binding environment chapter. It is unclear whether their reluctance to openly support the U.S. position — or similar language — is a negotiating tactic, the result of policy disagreement, or stems from potential conflicts with existing trade pacts, according to a Wyden aide.

The senators also point to the importance that other chapters in the proposed agreement, such as the investment chapter, not undermine the goals of the environment provisions. Environmental groups have criticized the U.S. government’s embrace of investment provisions that give foreign companies standing to challenge sovereign governments in third-party tribunals if they believe a country is unfairly discriminating against their ability to conduct business.

“This is key, as a strong and binding environment chapter — as critical as one is — can be severely undermined if we allow foreign corporations to attack governments’ environmental laws and policies in private tribunals, as the currently drafted investment chapter would allow,” said Ilana Solomon, trade representative at the Sierra Club.