sensor within 10 feet of each vessel, compressor, wellhead, manifold, or pump that could release enough H2S to result in atmospheric concentrations of 20 ppm. You may conduct a design analysis including dispersion modeling to determine a more effective or a more efficient placement of sensors. These pumps will also probably require completea replacement after 5 to 10 years in service. Big plunger pumps such as the Gaso, Wheatley, Oilwell, Gardner Denver, Kerr, B-Master can run for 40 to 50 years if properly mainained and rebuilt every 3 to 10 years depending on service conditions. Historically acknowledged as toxic gases, hydrogen sulfide (H<sub>2</sub>S) and nitric oxide (NO) are now recognized as the predominant members of a new family of signaling molecules, “gasotransmitters” in mammals. While H<sub>2</sub>S is biosynthesized by three constitutively expressed enzymes (CBS, CSE, and 3-MST) from L-cysteine and homocysteine, NO is generated endogenously ...