1.1 This guide covers appropriate responses for employers, building owners and operators, facility managers, health and safety professionals, public health authorities, and others: (1) to a concern that a manmade water system may be contaminated with the bacteria known as legionellae (see 6.1); and (2) to the identification of one or more cases of Legionnaires disease or Pontiac fever due to inhalation of airborne legionellae (see 6.3-6.5). Comprehensive and explicit recommendations to limit legionella multiplication in water systems and to disinfect potential sources of human exposure to legionellae are beyond this guides scope. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See 7.3 and 8.5 for specific hazard statements.