What is Envirofacts?

Envirofacts, http://www.epa.gov/enviro/ is a U.S. EPA based website that provides links to numerous environmental databases and managements systems in one site. You can find in-depth information on subject areas by selecting from a list of topics.
http://www.epa.gov/enviro/html/topics.html

Within these topics you can browse through the various databases mentioned below.

Waste:

Biennial Reporting, Brownfields, Superfund (CERCLIS), and Resource Conservation and Recovery Act Information

Water:

Information Collection Rule, National Drinking Water Contaminant Occurrence Database, and Permit Compliance System

Toxics:

Toxics Release Inventory

Air:

Aerometric Information Retrieval System, and UV Index (predicts ultra violet radiation)

Radiation:

RadNet (formerly Environmental Radiation Ambient Monitoring System), and Radiation Information Database

Land:

Brownfields, Superfund, Resource Conservation and Recovery Act Information

Other:

Facility Registry System, Location Information, and Grants Information System

Maps:

Enviromapper, Open Link, and Window to My Environment (WME)