Ilana Solomon, the director of the Sierra Club’s Responsible Trade Program, said the draft omits crucial language ensuring that increased trade will not lead to further environmental destruction.

“It rolls back key standards set by Congress to ensure that the environment chapters are legally enforceable, in the same way the commercial parts of free-trade agreements are,” Ms. Solomon said. The Sierra Club, the Natural Resources Defense Council and the World Wildlife Fund have been following the negotiations closely and are expected to release a report on Wednesday criticizing the draft.

American officials countered that they had put forward strong environmental proposals in the pact.

“It is an uphill battle, but we’re pushing hard,” said Michael Froman, the United States trade representative. “We have worked closely with the environmental community from the start and have made our commitment clear.” Mr. Froman said he continued to pursue a robust, enforceable environmental standard that he said would be stronger than those in previous free-trade agreements.

The draft documents are dated Nov. 24 and there has been one meeting since then.

The documents consist of the environmental chapter as well as a “Report from the Chairs,” which offers an unusual behind-the-scenes look into the divisive trade negotiations, until now shrouded in secrecy. The report indicates that the United States has been pushing for tough environmental provisions, particularly legally binding language that would provide for sanctions against participating countries for environmental violations. The United States is also insisting that the nations follow existing global environmental treaties.

Image Michael Froman, the United States trade representative, said, “We’re pushing hard.” Credit... Stephen Crowley/The New York Times

But many of those proposals are opposed by most or all of the other Pacific Rim nations working on the deal, including Australia, New Zealand, Canada, Mexico, Chile, Japan, Singapore, Malaysia, Brunei, Vietnam and Peru. Developing Asian countries, in particular, have long resisted outside efforts to enforce strong environmental controls, arguing that they could hurt their growing economies.