The Model Toxics Control Act (MTCA) identifies requirements for how cleanup decisions are made. Once an end-use, such as residential housing or industry, has been identified for a contaminated site, scientists and engineers work with the Washington State Department of Ecology to determine how clean the site needs to be using Methods A, B, or C. After this is done, they look at all of the technologies and other approaches for cleaning the site up and propose several potential approaches. To decide which approach is best, a disproportionate cost analysis (DCA) can be done. A DCA considers costs and benefits to make a final selection, but the approach that is chosen must meet several requirements, including: • • • •
Protect human health and the environment Comply with cleanup standards Comply with applicable state and federal laws Provide for compliance monitoring
Additional considerations include: • Use permanent solutions to the maximum extent practicable • Provide for a reasonable restoration time frame • Consider public concerns