TagMTCA(83)

WAC 173-340-740 from the Model Toxics Control Act (MTCA) Cleanup Regulation, published February 12, 2001, establishing unrestricted land use soil cleanup standards. Covers Method A, Method B (standard and modified), and petroleum mixture cleanup levels including Equations 740-1 through 740-3 for noncarcinogens and carcinogens. Specifies default exposure parameters: soil ingestion rate 200 mg/day, average body

This Washington State regulation (WAC 173-340-747) establishes methods for determining safe soil contamination levels that protect groundwater quality at cleanup sites. It outlines several scientific approaches, including three-phase and four-phase partitioning models, leaching tests, and empirical demonstrations, to calculate the maximum allowable concentration of hazardous substances in soil before they risk contaminating groundwater. The regulation requires that soil concentrations not cause groundwater cleanup level exceedances and not result in the buildup of nonaqueous phase liquids in or on groundwater.

Exhibit AR017360, Part IX Tables from MTCA Cleanup Regulation WAC 173-340-900, dated February 12, 2001. Contains Table 720-1, Method A Cleanup Levels for Ground Water, listing hazardous substances including arsenic, benzene, benzo(a)pyrene, cadmium, chromium, DDT, 1,2-dichloroethane (EDC), ethylbenzene, ethylene dibromide (EDB), lead, lindane, methylene chloride, mercury, MTBE, naphthalenes, PCB mixtures, radium 226, tetrachloroethylene, toluene, trichloroethylene,

A January 2001 letter and accompanying meeting notes document communications between the Port of Seattle and the Washington Department of Ecology regarding a groundwater contamination study at Seattle-Tacoma International Airport, conducted under the Model Toxics Control Act (MTCA) Agreed Order 97TC-N112. The records outline the scope of the study, which focuses on hydrogeologic investigation and a review of the Fuel Operations Area, and clarify that any necessary cleanup would be handled separately after the study's completion. Both parties discussed concerns about scope expansion and the process for addressing contaminated sites identified through the study.

A December 7, 2000 letter from the Port of Seattle to the Washington Department of Ecology responds to questions raised at a November 16, 2000 meeting regarding the Seattle-Tacoma International Airport Ground Water Study conducted under Agreed Order #97TC-122. The letter addresses the completion status of various research tasks, including hydrogeological surveys, contamination site identification, groundwater flow modeling, and pollution prevention for underground storage tank systems. The Port agrees with some of Ecology's assessments of incomplete tasks while disputing others, and clarifies its position on the scope of work required under the agreement.

Email chain (AR 017786-017788, DOE S-13:01 0884-0886) forwarded by Joan Marchioro (ATG) to Raymond Hellwig on November 22, 2000, originating from Peter Kmet to Chung K. Yee on September 11, 2000, marked not for production as deliberative. Discusses proposed new Method A soil cleanup levels under MTCA (Model Toxics Control Act), WAC 173-340-708(b), with attached

Email dated November 15, 2000 from Chung K. Yee to Kevin Fitzpatrick regarding Sea-Tac fill dirt, specifically the ‘Black’ virgin site where soil samples exceeded Method B 100X groundwater standards under MTCA (Model Toxics Control Act). The site holds 200,000 to 300,000 cubic yards of fill and is workable during winter months. Beth Clark arranged

In a October 2000 letter to the Port of Seattle, Water Resources Consulting LLC — writing on behalf of the Airport Communities Coalition — raised concerns about the SeaTac Aircraft Hydrant Fueling System project, arguing that construction should be delayed until an ongoing groundwater contamination study under the Model Toxics Control Act was completed. The letter criticized the project's environmental review (Declaration of Nonsignificance) for lacking specific details about leak detection, operating pressures, and contaminated soil management. The consultant warned that deep utility trenching could create preferential flow paths for existing fuel contaminant plumes, potentially threatening the groundwater supplies relied upon by nearby communities.

This October 2000 internal memo from Roger Nye to TCP Section Head Steve Alexander explains the history of the Agreed Order between Washington State Ecology and the Port of Seattle regarding environmental cleanup at Sea-Tac Airport. It describes how the Port agreed to conduct a large-scale groundwater evaluation under an Agreed Order, with the understanding that a risk-based cleanup remedy scenario would be developed if contamination risk proved low. The memo also notes that the Agreed Order intentionally excluded language about remedial actions, with Ecology reserving the right to formally intervene if cleanup became necessary.

Email chain dated September 11, 2000 among Washington State Department of Ecology staff (Chung K. Yee, Kevin Fitzpatrick, Peter Kmet) and ATG’s Joan Marchioro regarding clean fill criteria language for the 401 Water Quality Certification on the Sea-Tac Third Runway. Peter Kmet raises concerns about arsenic limits (proposed 20 vs. background 7-8 in Western Washington),