Most asbestos-related construction activities involve previously installed building materials. In particular, thermal system insulation and surfacing materials, such as flooring installed no later than 1980, are presumed to contain asbestos unless they are analyzed and shown to be asbestos-free. Building owners and employers have a responsibility to exercise diligence to identify any ACM and to communicate this information to the employees. OSHA's Construction Industry Standard for asbestos regulates all employers involved in construction work.