by Dave Righthouse – Senior Project Manager, Plant Operations

Recently at a NAES-operated facility, an environmental services contractor contacted the facility’s asset manager about installing a number of monitoring wells. The contractor proposed several sites for the wells, which would range from 15 to 30 feet in depth.

The contact started as a phone call that was followed up by an email to recap the discussion. The asset manager reminded the contractor that his personnel would require safety training and basic facility orientation before they could start any work. The email exchange included the proposed coordinates of the monitoring wells, which were to be drilled at various locations within the site confines.

The contractor was looking for approval to begin work and suggested a start date for the work. The asset manager responded that “on the surface everything looked good” and reminded the contractor to get in touch with site personnel for their safety orientation and walk-through. Site personnel provided the environmental contractor with underground piping diagrams and site plans.

The site walk-through was scheduled and the proposed monitoring wells were marked out. To be sure that the locales were safe for drilling, the contractor used a sonar device to detect any underground objects. However, the device proved accurate to a depth of only 6 feet due to the heavily compacted soil.

Once the mark-outs were completed, the site team scheduled the drilling contractor to begin work. The first two wells were drilled without incident. However, on the third well, after performing a soft-drill to a depth of 6 feet, the auger hit something hard at 9 feet below grade. The contractor backfilled the well and abandoned it. A couple of days later, the backfill had sunk significantly. After a second backfilling, the same sinking was observed. The site was excavated, which revealed that the drilling had punctured an active pipeline.

NAES conducted a root cause analysis, during which it was noted that the contractor had interpreted the words “on the surface everything looked good” to mean that the proposed well sites had been cleared for drilling. He didn’t refer to the drawings he had received because in his view, the site team had approved the proposed sites. The site team had assumed that the contractor had utilized the drawings and was simply safeguarding the process by using the sonar device. No one realized that the sonar device was only accurate to about 6 feet given the soil conditions.

In short, a simple statement that things looked good was taken as a work scope approval. The mindset of looking for approval – and reading it into a conversation – had led the contractor down a path that it was OK to proceed. Fortunately, the incident produced a relatively minor incident and may provide a much greater opportunity for teaching us how we can assure that things are safe before we begin work.

One question to ask in such cases as these is ‘How do we know it’s safe to proceed?’ If the answer doesn’t include hard, factual evidence that can be traced back to well-founded conclusions, then it’s time to stop and double-check. In this case, an offhand remark was taken as approval and resulted in a costly mishap.