During an MSHA inspection of the ""HP7 area"", H2S gas was found near barricade points from the water containment area that fluctuated under and over 25 ppm around the barricade. A ""K"" order was issued. The inspector made a phone call and was directed to make this a reportable incident categorized as an ""inundation"" at approximately 2:02 p.m. I reported to MSHA hotline at 2:10 p.m.