BURLINGTON, Vt., Jan. 5 – U.S. Sen. Bernie Sanders (I-Vt.) today asked the chief trade representative for the United States to turn over the full text of a proposed Trans-Pacific Partnership trade agreement.

The 12-nation pact, which could soon come before Congress, has been negotiated in secret but with input from corporations that stand to profit on the deal.

In a letter to United States Trade Representative Michael Froman, Sanders called it “troubling” and “unacceptable” that the only sources for Congress to assess what would be the largest global trade deal in history are a few leaked documents.

“It is incomprehensible to me that the leaders of major corporate interests who stand to gain enormous financial benefits from this agreement are actively involved in the writing of the TPP while, at the same time, the elected officials of this country, representing the American people, have little or no knowledge as to what is in it,” Sanders said in the letter.  “In my view, this is simply unacceptable.”

Proponents of the pact are pushing for a fast-track process for Congress to take up the deal with no opportunity to revise it.  Especially under those circumstances, Sanders said, members of Congress must be given time to read and analyze the agreement in order to consider the implications.

If Sanders’ request is turned down, the senator asked Froman to spell out the legal basis for a denial. “Please also explain why you think it is appropriate that the representatives of the largest financial institutions, pharmaceutical companies, oil companies, media conglomerate and other major corporate interests not only have access to some of these documents, but are also playing a major role in developing many of the key provisions in it,” Sanders added.  “Meanwhile, the people who will suffer the consequences of this treaty have been shut out of this process.”

Unless details of the deal are shared with members of Congress, Sanders also said he would introduce legislation to require that the contents of any trade agreement that the U.S. is negotiating would have to be made public at the request of any member of Congress.

To read Sanders’ letter, click here.