Wescott Plantation Methane Assessment

 

In June of 2007, the South Carolina Department of Health and Environment Control (SCDHEC) requested that the EPA Emergency Response and Removal Branch (ERRB) perform a removal site evaluation (RSE) at Wescott Plantation. Explosive levels of methane had been noted at two homes in Wescott Plantation, a local residential subdivision, in previous independent reports.

After conducting a briefing on Tuesday, June 26th, 2007 with the State, the EPA On-Scene Coordinator (OSC) determined that it was necessary to conduct air monitoring for methane in local homes. A list of homeowners that had requested air monitoring was available through the local homeowners association. The State estimated that between 20 and 30 homes would request the service. Notifications were made to the North Charleston Fire Department, Police Department, North Charleston City Management, Dorchester County, and SCDHEC. The OSC also consulted with the Agency for Toxic Substances Disease Registry (ATSDR).

At 10:00 am on Wednesday, June 27, 2007, the OSC conducted a Unified Command meeting with members of the above notified parties at the fire station nearest to Wescott Plantation homes. In addition, several representatives of the homebuilder (Lennar) were in attendance.

Public relations were coordinated through an EPA Community Involvement Coordinator and included representatives from SCDHEC and the City of North Charleston. Fact sheets were developed and distributed to local residents.

The City of North Charleston provided a Mobile Command Post (MCP), manned by the North Charleston Fire Department and represented the City through Fire Chief, Leonard Judge, Jr.

SCDHEC provided additional support through program management, emergency responder, and community involvement personnel. SCDHEC personnel were used to contact residents, briefing the OSC on historical areas of concern, and provide oversight after EPA's departure.

Lennar provided resources including access to previous documentation and contractor representatives concerning methane monitoring and remediation. In addition, they also provided with requested historical aerial pictures and plot development overlay.

Air monitoring was conducted in 19 homes over a two day period. All homes were significantly below the lower explosive limit (LEL) for methane, including the two original homes of concern. All homeowners were notified of their individual results via letter report on June 29, 2007. Updated assessment information fact sheets were distributed to concerned citizens.

Additional requests for air monitoring for methane will be conducted by Lennar with oversight from the SCDHEC district emergency responder.

In recent months, subsurface venting systems had been installed at the request of Lennar, at the two homes in which elevated levels of methane were found. Based on the ERRB monitoring data, both these systems appeared to have significantly reduced the once higher levels of methane.

Concerns were expressed by homeowners over the possibility of additional gases being emitted into their homes from the subsurface. After reviewing earlier monitoring results, the decision was made to sample the existing subsurface soil venting system in the two homes that had previously displayed higher levels of methane. The analytical results indicated no total organic or individual organic constituents which would present a public health threat.

The final RSE Pollution Report (POLREP) is available as of October 15th. Based on a review of the information gathered during this evaluation, the RSE recommends no further action. The complete RSE as well as other documents of interest can be found under the documents section of this website.


For additional information, visit the Pollution Report (POLREPS) section.