Hi Bob. We just found out that our "Professional Plumber" has not put one vent pipe into our house. "We just did extensive renovations." He also installed the new heater and water tank, which our gas company closed down until repairs are done. My question?? Our plumber's,( yes, two plumbers) say that we have been subjected to vapours from our septic tank for about 7 months. We have been getting headaches, nose bleeds, sore throats, sinus problems, not to mention fatigue, muscle cramps, ect,,,. This summer has been bad, making the accumulation of the gasses a lot higher being that the windows were left shut. I can not find any articles on these gasses and the results of being exposed to them. Health and Welfare say that the gasses are extremely harmful and combustable?? Can you help me?? We are getting it fixed! Thank you.