Section 30.695 - General Operating Requirements(1) Hazardous wastes and other materials (e.g., treatment reagents) which are incompatible with the material of construction of the tank shall not be placed in the tank unless the tank is protected from accelerated corrosion, erosion or abrasion through the use of: (a) An inner liner or coating which is compatible with the hazardous waste or other material and which is free of leaks, cracks, holes and other deterioration; or(b) Alternate means of protection (e.g., cathodic protection or corrosion inhibitors).(2) The owner or operator shall use appropriate controls and practices to prevent overfilling (e.g., waste feed cut-off or by-pass system to standby tank). (a) Controls to prevent overfilling (e.g., waste feed cut-off or by-pass system to standby tank); and(b) For uncovered tanks, maintenance of sufficient freeboard to prevent overtopping by wave or wind action or by precipitation.(3) Throughout the period of storage or treatment, each tank shall be clearly marked and labelled in a manner which clearly identifies, in words, the hazardous waste(s) being stored or treated in the tank (e.g., acetone, toluene) and the hazard(s) associated with the hazardous waste (e.g., ignitable, toxic, dangerous when wet). Each tank shall also be marked clearly with the words "Hazardous Waste".(4) In the event of a release of hazardous waste from the tank system, the owner or operator shall comply with 310 CMR 30.697.(5) A tank holding hazardous waste shall always be closed during storage, except when waste is being added or removed.Amended by Mass Register Issue 1278, eff. 1/16/2015.