The Chlorine Dioxide treatment is intended for use in hospitals due to the effectiveness of chlorine dioxide in controlling pathogens such as Legionella pneumophila, Stenotrophomonas maltophilia, and Mycobacterium avium complex. Shock disinfection is the application of a disinfectant to a system at concentration above normal dosages, for a limited time, to achieve a specific goal.  An institution engaging in shock disinfection on a temporary basis does not make it a Consecutive PWS. Such an arrangement is the responsibility of the hospital and its designated engineer/consultant, as well as the local water authority. The proponent must follow the following procedure:

  • A hospital (or any other facility connected to a PWS) must develop a chlorine dioxide shock disinfection plan.
  • The plan must address how to provide the concentrations specified throughout the treatment area and how to monitor those concentrations.
  • The Plan must be signed by a professional engineer registered in Massachusetts and be submitted to the PWS for approval with a copy to MassDEP regional office (for information only, but MassDEP staff may comment if the office has the resources to review).
  • The engineer must be knowledgeable about the plumbing at the facility and chlorine dioxide shock treatment procedures.
  • The plan must address how to isolate the portions of the plumbing system to be disinfected in order to assure that no water with high concentrations of chlorine dioxide enters those portions of the plumbing system that are actively providing potable water.
  • At a minimum, a double block and bleed or more stringent method of isolation must be used to separate the high-chlorine-dioxide water from active plumbing.
  • The plan must address air quality, disposal requirements, and the safety of the chlorine dioxide generating/transportation process.
  • MassDEP encourages the engineer and PWS to enlist the aid of the PWS's Cross Connection Control Plan Manager and Surveyor.
  • The plan must identify notification procedures in order to assure that the PWS is duly notified of the initiation of the plan and that all hospital staff that should be notified of the procedure are notified.
  • The plan must be implemented under general supervision of the engineer and/or certified operator with a 2T license.  

Please submit a copy of the plan to the appropriate MassDEP regional office:

Western Region : Dan Laprade, 413-755-2289

Central Region : Nora Hanley, 508-767-2720

Northeast Region : Hilary Jean, 978-694-3229

Southeast Region : Giliane Tardieu, 508-946-2789, or Scott Sayers, 508-946-2780