Appendix 4-B - Interpretation of Routine Legionella Culture Results from Covered Facilities

Appendix 4-B

Interpretation of Routine1 Legionella Culture Results from Covered Facilities
Percentage of Positive Legionella Test Sites
Response
< 30% Maintain environmental assessment and Legionella monitoring in accordance with the sampling and management plan.
≥ 30%

o  Immediately institute short-term control measures2 in accordance with the direction of a qualified professional,3 and notify the department.

o The water system shall be re-sampled no sooner than 7 days and no later than 4 weeks after disinfection to determine the efficacy of the treatment. o For persistent results, as determined by the department, showing ≥ 30% positive sites, long-term control measures5 shall be implemented in accordance with the direction of a qualified professional3 and the department.

  • Retreat and retest. If retest is ≥ 30% positive, repeat short-term control measures.2
  • With receipt of results < 30% positive4, resume monitoring in accordance with the sampling and management plan.

o  For persistent results, as determined by the department, showing ≥ 30% positive sites, long-term control measures5 shall be implemented in accordance with the direction of a qualified professional3 and the department.

1 In the event that one or more cases of legionellosis are, or may be, associated with the facility, the sampling interpretation shall be in accordance with the direction of a qualified professional and the department.

2 Short-term control measures are temporary interventions that may include, but are not limited to, heating and flushing the water system, hyperchlorination, or the temporary installation of treatment such as copper silver ionization (CSI).

3 Control measures shall be conducted in accordance with the direction of a qualified professional. A qualified professional is a New York State licensed professional engineer; certified industrial hygienist; certified water technologist; environmental consultant or water treatment professional with training and experience performing assessments and sampling in accordance with current standard industry protocols.

4 Positive samples should be minimized.

5 Long-term control measures may include supplemental disinfection treatments.
 

 

Effective Date: 
Wednesday, July 6, 2016
Statutory Authority: 
Public Health Law, Section 225(5)(a)