Worth knowing: Some of the organizations with access to TPP negotiations.

International Brotherhood of Teamsters

United Auto Workers

Audubon Naturalist Society

Boston University

Brookings Institution

American Society of Civil Engineers

American Society of Mechanical Engineers

Consumers Union

Environmental Defense Fund

International Fund for Animal Welfare

The Humane Society of the United States

United Food and Commercial Workers Union

United Steelworkers

Now, granted there are many times more corporate and business-oriented interests being represented than these philanthropic and labor union groups, and none of them have much pull outside (or even really inside) the United States. But it's worth knowing that the groups above have the same access to the process as these business groups.

The source is an anti-TPP blog post from a site whose credibility I have no clue about (it's apparently a religious liberal site), but since it's arguing against TPP, the fact that it provides mitigating information suggests it's legit.