Incident Report - Communications Lapse and Above-Standard Dust Readings - August 4, 2008

On Monday, August 4, 2008, a communications lapse occurred when the contractor (SCE) did not notify AGC that excavation of topsoil over battery casings would occur. This excavation was performed to allow SCE to pump water from the existing basin as allowed in the 100% Design. Even though the action is something that is allowed, AGC needed to have air monitors set up prior to movement of contaminated soils, so that the effectiveness of the dust control measures could be monitored. The delay was very brief because AGC people onsite saw the excavation and set up the monitors within minutes. Nonetheless, this was the second communications lapse within a week, and shows that further work is still needed on site communications.

In the daily operations meeting later on Monday (as well as in earlier discussions after the excavation occurred), the importance of communicating these types of changes in site activities was stressed.

When the air monitors were set up, the excavation was already completed and the pumping of water was taking place. The air monitors recorded particulate matter (e.g., dust) slightly in excess of the relevant performance standard for excavation of battery casing material contained in the 100% Design. It was determined that no corrective action was necessary based on several factors:

· The above-standard readings were observed prior to when the instrument was fully stabilized, so they may not be representative of the actual conditions at the time.

· There was no visible dust.

· The excavation had occurred through wet soils, decreasing the chance of dust being released.

· The readings upwind of the excavation were also slightly elevated.

Review of the data at the end of the day indicated that there were some half hour averages that were above the standard that were measured when there was no excavation taking place, only pumping of water. The performance standard for when battery casings are excavated is extremely low. As in this case, the performance standard can sometimes be below the level of dust in upwind samples – that is, dust having nothing to do with site activities. So a brief reading that is over this standard is neither unexpected nor alarming and may not warrant a change in how work is being performed. It is a measure of the extreme care that will be taken when excavating these materials. We are continuing to review the standards as well as the equipment used to measure them and evaluating how the work is being performed in order to complete the excavations in a safe manner.

Throop Borough was notified of both the communications lapse and the above-standard dust readings.

Page Last Modified Thursday November 12, 2009 12:32:09 PM