Administrative agencies are primarily concerned with rulemaking and adjudication. Rulemaking is discussed on the page "Regulations and Interpretive Rules." Adjudication is an agency decision regarding permitting, licensing, or enforcement of rules and regulations. Adjudicators may be administrative law judges (ALJs) and are not Article III judges - meaning they are a part of the legislative process and not the judicial branch. Agency adjudicators are civil service employees that are not appointed for life and subject to impeachment.
Federal administrative decisions are often released on agency websites and available on legal subscription databases like Westlaw, Lexis Advance, and Bloomberg Law. These decisions may also be published in reporters like judicial decisions. See Table 1 in the Bluebook - it lists federal entities and where some of the materials are published. Many of these reporters will be available through the HeinOnline U.S. Federal Agency Documents collection. Note that the Bluebook is not comprehensive and may not reflect up-to-date or easy to use electronic information.
IMPORTANT: Not all administrative decisions will be precedent decisions - this means they do not have precedential effect for future adjudications and should not be solely relied on for relief. A non-precedent decision is binding only on the parties involved.
As with other information published on agency websites, it would benefit you to become familiar with these websites to see what is and is not available. A good resource for finding administrative decisions free online for many agencies is the guide "Administrative Decisions" from the University of Virginia.
Department of the Interior
Environmental Protection Agency
Louisiana DEQ administrative decisions are available on Westlaw (from 1981) and Lexis (from 1984). DEQ and the Department of Natural Resources have their own document systems with a variety of included documents. At the time of writing, these websites are not user friendly. If you work with these departments, you will need to take the time to familiarize yourself with these systems.
Louisiana has a centralized Division of Administrative Law that handles a variety of hearings, including from DEQ, DNR, and DPSC (transportation of hazardous materials). Certain agencies and actions are exempt; see LA RS 49:991 et seq., in particular 992(D)(1)-(9).