Correct.
It extends a step further even if you weren't a contractor to the pipeline company.
If you were a construction worker working near a pipeline and damaged the pipeline and caused damages, the pipeline company is responsible even though you weren't working for the pipeline company and damaged the pipeline and caused harm and costs. The pipeline company would still be under absolute liability and would have to clean up and pay for it.
They could then, after the fact, pursue me as the construction company worker to recover those costs that they might have incurred, but that will happen outside of the NEB Act and under general tort law or the appropriate legal frame.