It has various maps data, including lake ice over time, et cetera. It looks kind of old and unmaintained, though. Some dead links. However, it's not very big.
One problem I encountered is that certain folders, for example, ./geodata.epa.gov/arcgis/rest/services/OAR_OAQPS are also files. And, the files (which are directory listings) are downloaded first, and prevent any lower-level stuff from being downloaded.
Where I noticed it, I solved it by moving x/y to x/y/index.html and mkdir x/y .