Hunters Point Power Plant Cleanup ‐ Air Monitoring Results

Following is an overview of the air monitoring results for airborne naturally occurring asbestos that PG&E collected at the former Hunters Point Power Plant site from June 20 to July 1, 2011, on days that work was being conducted. For this period, there were two days with readings above the Trigger Level, a conservative threshold at which additional dust controls will be implemented. A summary of the readings is below.

June 20 to June 24, 2011

1: Activities taking reading: Underground demolition and fence‐ line sampling.

Actions taken: Underground demolition work in the area was suspended on June 27. On June 25, Soiltac (a soil adhesive) was applied to help reduce potential for airborne NOA. One more water truck was added to support fence‐line soil sampling, a low impact activity, and the backfilling of excavations with clean soil. All personnel were reminded of the established dust measure protocols.

June 27 to July 1, 2011

1: Activities taking place in areas of reading:

• Area B – Concrete demolition and over‐ excavation of remedial areas.
• Area C/D ‐Backfilling with clean soil.

Actions taken:

The site incurred an unusual rain event in which 0.89 inches of rain was received. The following actions were taken. All soil disturbing activities for the following day (6/30/11) were suspended until TEM results were received for June 29. In the future when rain events are in the forecast, an additional application of Soiltac will be applied to all areas.