In 1980, Congress passed the Comprehensive Environmental Response Compensation and Liability Act (CERCLA), commonly called the "Superfund" Act, and began applying it to abandoned industrial sites. Under CERCLA, additional responsibilities and authorities were delegated to DoD. CERCLA set up the original "Superfund" funding for cleanups of hazardous waste sites. Sites eligible for cleanup using Superfund are listed by EPA on the National Priorities List (NPL).

In 1986, Congress passed the Superfund Amendments and Reauthorization Act (SARA), which made changes to CERCLA. An important provision of SARA included federal facilities in the Superfund process. DoD set up the Defense Environmental Restoration Account (DERA) to fund studies and cleanups at military installations. Federal facilities are not eligible for Superfund cleanup funds, but are still subject to listing on the NPL. Vieques was listed on the NPL in 2005.

1. The first step in the CERCLA process is site identification. In the Preliminary Assessment/Site Investigation (PA/SI), an installation is surveyed to determine which activities ma y have generated hazardous wastes, what those wastes were, and what was done with them. This includes reviews of old records, interviews with current and former employees, and an inspection of the installation.

Specific sites are identified where chemicals may have been released to the environment, preliminary soil and water samples are taken, and a determination is made whether or not further investigation is warranted at each site. If a site poses no significant threat to human health or the environment, it is eliminated from further consideration (No Further Action).

2. The second step, for sites that may require cleanup, is a Remedial Investigation (RI). During the RI, monitoring wells may be installed and samples of soil, groundwater, surface water, and sediment are collected for laboratory analysis. The RI, including human health and ecological risk assessment studies, determine which wastes are present, where they are, whether they are moving into the groundwater, and whether there is a risk to public health and the environment.

If risks from site-related chemicals are above the EPA target risk range for human health or the environment, a Feasibility Study (FS) is conducted. Based on data from the RI, the FS determines the best technology for cleaning up a site to protect both humans and the environment from contaminants at the site.

Sites that pose an imminent threat to public health or the environment are cleaned up immediately with removal actions, at any point in the study process. A removal action can also be used at a site that would be safe with land use controls, in order to allow unrestricted use. An Environmental Evaluation/Cost Analysis is prepared and the public is invited to comment. After a removal action has been conducted, data collected in the RI is used to determine whether or not additional cleanup is needed to reduce long-term risks to the environment.

3. The regulatory agencies select a remedial alternative based upon nine criteria. The preferred alternative (which could include No Further Action) is described in detail in a Proposed Remedial Action Plan (PRAP), written expressly for public review and comment.

4. Once the public has had a chance to comment on the selected alternative, a Record of Decision (ROD) is issued.

5. A Remedial Design is developed and approved. Then the actual cleanup, the Remedial Action, begins. Remedy in Place is an important milestone in the cleanup process. At this point, the selected remedy is in place and is operating properly and successfully to meet cleanup objectives. The site is monitored to ensure that the selected remedial alternative has worked. Sampling and analysis may be required to confirm that the site contaminants are no longer present above acceptable action levels and to begin site closure activities.

6. When cleanup work is complete, or if the investigation process reveals that cleanup is not required, a site moves into the Response Complete (RC) category. A site does not have to go through every phase of the CERCLA process to achieve Response Complete.