A natural gas facility experienced a major underground mercaptan spill, first identified through community odor calls. More than 400 odor calls came in from the surrounding community before excavation could begin. The spill drew media attention and regulatory involvement, and a potential facility shutdown carried lost revenue in the seven figures per day. Mercaptan is detectable at concentrations of parts per billion, so any disturbance of contaminated soil during a conventional excavation would have produced new odor releases across the community.
Approach
The response was built around atmospheric isolation. MRR engineered a fully enclosed excavation operation held under negative pressure, with carbon filtration treating all captured air before discharge. The work required specialized equipment deployed for the first time on this type of project. No air left the enclosure unfiltered.
Crews operated 24 hours a day through winter conditions while the plant remained in operation. Approximately two thousand tons of contaminated soil were excavated and treated on-site. Real-time air monitoring ran continuously throughout the project to verify containment performance.
Outcome
The on-site work ran four months from mobilization to completion. Laboratory testing confirmed no detectable mercaptan remaining in the soil. Odor calls from the community stopped once containment was established, and the facility operated as expected for the duration of the work, avoiding the shutdown scenario entirely. Documentation of the full response, including air monitoring and soil testing records, was provided to the client and stood up to regulatory review. The client reported complete satisfaction with the response.
