Safety system for operations on a digester in the presence of biogas , the system comprising: - at least one digester for biogas production arranged on a support ground comprising - a side wall extending from the support ground along a direction transverse thereto and defining a basin , - a cover associated with the side wall and defining with the basin a tank , and - active means configured to act inside the tank ; - the at least one digester having: - one or more active portions formed on the side wall and/or the cover and associated with the active means ; - one or more support surfaces substantially parallel to the support ground and associated with the side wall or the support ground ; - biogas collection means in fluid communication with the tank of the at least one digester and configured to extract the produced biogas comprising methane and carbon dioxide; - a separation unit associated with the biogas collection means and configured to separate methane from carbon dioxide included in the produced biogas; characterised in that it comprises: - a cover element removably fixed to an active portion of the digester and to a support surface proximate to the relative active portion , the cover element defining with the active portion of the digester a safety chamber in fluid communication with the separation unit to receive the separated carbon dioxide and generate a methane inert atmosphere near the active portion . - at least one digester for biogas production arranged on a support ground comprising - a side wall extending from the support ground along a direction transverse thereto and defining a basin , - a cover associated with the side wall and defining with the basin a tank , and - active means configured to act inside the tank ; - a side wall extending from the support ground along a direction transverse thereto and defining a basin , - a cover associated with the side wall and defining with the basin a tank , and - active means configured to act inside the tank ; - the at least one digester having: - one or more active portions formed on the side wall and/or the cover and associated with the active means ; - one or more support surfaces substantially parallel to the support ground and associated with the side wall or the support ground ; - one or more active portions formed on the side wall and/or the cover and associated with the active means ; - one or more support surfaces substantially parallel to the support ground and associated with the side wall or the support ground ; - biogas collection means in fluid communication with the tank of the at least one digester and configured to extract the produced biogas comprising methane and carbon dioxide; - a separation unit associated with the biogas collection means and configured to separate methane from carbon dioxide included in the produced biogas; - a cover element removably fixed to an active portion of the digester and to a support surface proximate to the relative active portion , the cover element defining with the active portion of the digester a safety chamber in fluid communication with the separation unit to receive the separated carbon dioxide and generate a methane inert atmosphere near the active portion . <EOS>