The state Department of Environmental Protection has concluded that a March 9 landslide that destroyed one home and caused the evacuation of four others in Pitcairn and Monroeville was not caused by blasting or other activities at the nearby Waste Management landfill in Monroeville.

The determination was announced in a letter to state Sen. Sean Logan, who last month asked the DEP to conduct a second inspection of the slide site.

According to the DEP inspectors, there is evidence of numerous historic landslides of "red bed" clay soils in the area, including on the hillside where the latest slide occurred. The red bed clays are slippery layers of soil and rock prone to slippage.

The DEP letter also said the landfill blasting occurred at a distance from the site that would not cause the slope to fail. Additional measurements will be made by the DEP during future blasting as a precaution.

In the last year, 23 inspections for construction activities were conducted by the DEP's waste management staff, 13 blasting inspections were done at the landfill by the department's mining bureau staff and the Allegheny County Health Department did 13 inspections. No violations were noted during any of those inspections, the DEP letter said.

Mr. Logan was able to secure funding to demolish the damaged home, stabilize the hillside and conduct an engineering study to find a way to prevent another landslide.