A cast stainless steel vacuum pump element failed after 10 years of service in a geothermal power plant where it was used to provide vacuum for operation of a direct contact condenser operating at 0.1 bar. The environment encountered included some wetness and non-condensable gases CO2, H2S, NH3 from the geothermal steam and some O2 derived from the recirculating cooling water taken from the cooling tower coldwell. The primary damage mechanisms were localized pitting corrosion and Stress Corrosion Cracking (SCC) in the aerated sulfur containing environment. The source of the stress was a combination of service loads and residual stress in the type 316 alloy CF8M (UNS J92900) casting. This paper provides a summary of the failure investigation work and compares the observed damage mechanisms with those seen previously in Slow Strain Rate tests in simulated geothermal power station recirculating cooling water and with heated U-Bends with a drip solution containing low levels of chloride and sulfide. Identification of the primary damage mechanisms facilitated the development of guidelines for determining the replacement material criteria.