(D) Control Actions: Prevent Additional Exposure: Assume that all potential sources of contamination are contaminated and treat them accordingly. This includes hot and cold domestic water, cooling towers, humidifiers, and any other potential sources of water exposure. Control actions need not require facility shutdown. Temporary provisions including the following can allow work to continue: (a) Supply bottled water for drinking. (b) Shutdown water heaters to eliminate hot-water access. (c) Use temporary cooling towers to allow work to continue. Shutdown: A member of the building maintenance, engineering staff, or expert outside consultant who has a working knowledge of the system's design and current operation can explain how the water system operates and the proper procedure for a controlled shutdown. Treatment: (a) The treatment of potential sources of contamination following inspection and water sampling is described for specific operating systems in Section II. (b) After treatment, collect and analyze water samples for CFU of LDB to determine the effectiveness of the treatment. Upon re-use of a water system following treatment, maintenance and water sampling are essential to ensure that maintenance continues to be effective. See more from topic source: https://www.osha.gov/html/a-z-index.html