Much of the content on eco-usa relies on a variety of sources. This page is a partial list of those resources, sometimes with links and brief annotations.

Agency for Toxic Substances and Disease Registry. ATSDR is one of the best sources of online information about toxic chemicals and their effects. See especially the Toxicological Profiles.

Integrated Risk Information System. IRIS is U.S. EPA's online repository of information about risks associated with chemical exposures.

International Agency for Research on Cancer. IARC publishes a series of Monographs on the Evaluation of Carcinogenic Risks to Humans, and a List of Agents, arranged alphabetically.

National Park Service. National Parks, National Seashores and Lakeshores, National Monuments, and more. Generally well organized and an all-round tremendous resource.

Superfund Program. U.S. EPA's Superfund Program has an enormous web presence, though there's so much information organized in so many different ways that it can be difficult to find what you're looking for. The purpose of the Superfund Sites section of Eco-USA is to try and gather, organize, and present some of the most basic data.

United States Environmental Protection Agency. The U.S. EPA website is a sprawling affair; among other challenges, each of EPA's ten regions appears to operate their own subsites with differing formats and organization. As a result, finding what you seek can be a real challenge. In many cases, a Google search is your best option.

United States Fish and Wildlife Service. These are the folks who, among other things, operate the system of National Wildlife Refuges. Their website includes a directory of wildlife refuges, organized by state.

United States Forest Service. The Forest Service website has information about National Forests and National Grasslands, often including maps and camping/recreational opportunities.