After Remedy Selection
Following remedy selection decision, the remedy is designed, constructed, and operated. Once an active remedy is operating properly and successfully, it is considered to have met the EPA Construction Complete milestone. Operation and maintenance continue as long as an active remedy is needed to be protective. Optimization evaluations and five-year reviews are performed if chemical concentrations remain above unrestricted use levels in groundwater, soil, soil vapor, and other media (EPA, 2001a). As described in greater detail in Chapter 7, at these later stages monitoring data may be gathered, the remedy may be adjusted, and institutional controls (designed to minimize the potential for human exposure to residual contamination and/or protect the integrity of the remedy) are imposed. According to the NCP, institutional controls are supposed to supplement, not substitute for, active remediation “unless such active measures are determined not to be practicable, based on the balancing of trade-offs among alternatives that is conducted during remedy selection” [40 CFR § 300.430(a)(iii)(D)].
RCRA Corrective Action
Congress enacted RCRA in 1976 to regulate, by permit, the treatment, storage, and disposal of hazardous wastes. In 1984 it amended the law to regulate cleanup at facilities with RCRA permits (40 CFR section 264.101). Though RCRA is a federal law, most RCRA implementation is conducted by the states and territories. Today 43 states and territories have been delegated primacy over their RCRA Corrective Action programs. Therefore, there is more variation in RCRA oversight than under EPA’s CERCLA program.
The RCRA remedy selection process and criteria are generally similar to the CERCLA process (EPA, 1996b, 1997a, 2011a). Implementation of corrective action can vary from site to site (and state and state) but it invariably begins with an evaluation of site conditions through an RCRA facility assessment conducted by either EPA or the authorized state. Similar to the Preliminary Assessment/Site Inspection phase of CERCLA, this involves examination of the facility’s solid waste management units to determine if a release occurred or if the potential for a future release exists. Interim action to stop the spread of contamination or provide an alternate source of drinking water may be required during this stage. Additional information can be necessary to support interim actions and can be obtained by the site owner through an RCRA Facility Investigation. This investigation involves sampling and modeling to determine the nature and extent of contamination, the site hydrogeology, and the source zone architecture, similar