depth was 0.0? Does that mean they did it on or very near the surface?
With teleseismology, it is not easy to discriminate depths of less than a kilometer...
Air sampling should very soon reveal if it was shallow and/or "vented" to atmosphere. My bet is that it did vent, (the NKGooks aren't sophisticated enough to contain it) and air-sampling aircraft will soon detect it and provide samples for analysis.