This manual is mainly for two groups: employers whose businesses include the use of chlorine gas for water or sewage treatment; and workers who work with or around chlorine gas, including those who repair or maintain chlorine systems. Employers will find information on what they need to do to comply with the Regulation and to ensure a safe environment both for workers and for communities around facilities in which chlorine is stored or used. Workers will find information that will help them work safely around chlorine.