Investigation Protocol

  1. Initiate Environmental Investigation Response Protocol
    1. The Office of Epidemiology and Disease Surveillance and EH will respond to every reported case of legionellosis, including sporadic cases.
    2. EH will schedule the site visit with the affected facility as soon as practical from the Office of Epidemiology and Disease Surveillance to EH notification. The facility environmental assessment and sampling will not be scheduled for nor will it occur on a Friday.
    3. Once necessary and sufficient information is made available to clearly identify the area of concern, the Special Programs EH Supervisor will advise the affected facility to schedule the environmental assessment and sampling to occur on its property. The appointment will be made so that there is at least 24 hours, but no more than 72 hours, between the contact time of the official notification and the scheduled site visit. The site visit should be held first thing in the morning.
    4. The Centers for Disease Control and Prevention (CDC) form, “Environmental Assessment of Water Systems,” will be sent to the facility representative via email after the site visit is scheduled so that the facility may gather the pertinent information and complete the form before the meeting.
  2. Health and Safety Requirements During the Environmental Assessment
    1. During an environmental investigation of a facility associated with a confirmed or suspected case or cases of legionellosis, the Legionella Investigation Team members conducting the environmental assessment and collecting samples during the investigation may be exposed to Legionella pneumophila (Lp) or other pathogenic forms of Legionella spp. When appropriate, health district and facility staff should follow all respiratory protection requirements to prevent possible exposure to Legionella.
    2. Health District and facility staff should also be aware of other hazards, such as slips, trips and falls in slippery or dangerous areas; electrical shock hazards around water or equipment; and overhead hazards where staff might strike their heads. Staff should wear appropriate PPE such as non-slip shoes, safety glasses, hard hats, nitrile gloves and clothes without entrapment hazards such as ties or loose straps.
    3. During the planning phase, potential hazards are identified and the appropriate PPE will be obtained before beginning the onsite assessment.
  3. Environmental Investigation: Facility Preparatory MeetingThe Legionella Investigation Team, including possible Office of Epidemiology and Disease Surveillance representatives, will meet with facility representatives at the site visit to:
    1. Deliver official notification validating the guests’ stay with a letter of the initial report of the case of legionellosis, including a formal request to access affected room(s).
    2. Discuss Legionella life cycle (ecology), growth, release into the environment, sources and the bacterium’s ability to cause disease (pathogenicity).
    3. Discuss diagnosing, investigating and reporting of cases, including how the case was identified to the health district.
    4. Get the room number(s) from the facility, if necessary.
    5. Request the following records from the first of the month that is at least 60 days before the case stayed to present (date of site visit):
      1. Water management plan.
      2. Recent Legionella sampling results.
      3. Schematic of the plumbing system of the facility.
      4. Pool/spa records.
      5. Cooling tower maintenance logs.
      6. Hot water maintenance logs.
      7. Water mister maintenance logs.
    6. Require the facility to provide reasonable access to affected room(s), as per Regulations Governing the Sanitation and Safety of Public Accommodation Facilities, Section 11, and any associated areas impacting the affected room(s) and the water systems.
    7. Schedule the investigation and associated sampling events, including:
      1. A comprehensive environmental assessment.
      2. Sampling events, as many as are necessary to determine source of Legionella and document remediation activities.
      3. A walk of the affected property to identify potential sources of exposure to Legionella.
  4. Environmental Assessment: General Instructions The Legionella Investigation Team will:
    1. Use CDC and other standardized forms to completely document the environmental assessment at the affected facility.
    2. Interview any facility staff who may have knowledge of the case(s) or water systems within the facility.
    3. Collect as much information as possible. Utilize the CDC or other forms as guidelines to ascertain all relevant information is captured. Any information not readily available during the initial investigation may be filled out by facility staff and submitted within the specified timeframe to the health district.
  5. Environmental Assessment: Walk-Through of Property The Legionella Investigation Team will look at specific areas and document the conditions found within the facility that are most likely the sources of Legionella, such as:
    1. Cooling towers.
    2. Public bathing places (permitted bodies of water), spas and swimming pools.
      1. The investigators check sanitizer levels, pH, total alkalinity, and cyanuric acid levels.
      2. The investigators check temperature.
      3. If any condition is noted that necessitates closure of the body of water, the body of water will be closed. If any body of water is closed, then the routine assigned EHS shall be notified.
    3. Fountains
      1. The investigators check sanitizer levels.
    4. Water misters.
    5. Hot water heaters.
  6. Environmental Assessment: Water Sampling The Legionella Investigation Team will select and complete water sampling within identified areas, as follows:
    1. Room selection will be based on where the case stayed.
    2. Samples will be taken from all sinks, bathtubs, showers or similar fixtures in the room.
      1. Any easily accessible thermostatic cold mixing valve on hot water systems that can be accessed without the use of tools will be turned off.
    3. Samples will be taken from the room where the case stayed.
    4. Samples will be taken from the distal room on the riser where the case stayed.
    5. If possible, a sample will be taken from the return of the hot water loop of the riser where the case stayed.
    6. Samples from locations in guest rooms will include:
      1. A sample of cold water will be taken on first draw.
      2. A sample of cold water will be taken after a one minute flush.
      3. A sample of hot water will be taken on first draw.
      4. A sample of hot water will be taken after a one minute flush.
      5. An environmental swab of each fixture and the corresponding aerator will be taken.
    7. Complete documentation of the data and log times the samples were collected.
    8. Bulk water samples taken will be one liter.
    9. If the facility requests split sampling, then the facility will bear the handling costs, which include:
      1. Purchase of supplies including, but not limited to, the two-liter sample bottles,
      2. Sample processing expenses, and
      3. The manpower to assist in conducting such sampling.
    10. A two-liter sample will be collected in a sterile bottle. One liter of the sample will be poured into the health district one-liter sample container. The remaining sample will then be transferred to the facility for its use.
    11. Samples will be packed in insulated containers with frozen cold packs.
    12. Samples will be shipped to a CDC ELITE certified laboratory.
  7. Results of Water Samples and Environmental Specimens The Legionella Investigation Team will direct the following actions to occur, based on the laboratory results:
    1. If a bulk water sample from any guest room fixture has a result of greater than 10 cfu/ml of the target organism in any location, then the riser will be remediated.
    2. If water or environmental swab samples from two or more different fixtures have a result of less than 10 cfu/ml, but do not report as a non-detect of the target organism, then remediation will be required for that riser in the facility.
    3. If environmental swabs indicate the presence of the target organism in more than one fixture, then the riser will be remediated.
    4. If a single water sample or environmental swab returns with results less than 10 cfu/ml, but is the target organism for the specimen used to diagnose the case individual, then the health district will determine what type of remediation is required.
    5. Environmental samples collected from areas that are not guest room fixtures must meet OSHA standards. If the samples do not meet OSHA standards, then remediation of the system will be required.
    6. The following requirements are from the OSHA standard for Legionella control:
      1. Domestic water=10 cfu/ml or less,
      2. Misting water systems=1 cfu/ml or less,
      3. Cooling tower water=100 cfu/ml or less.
  8. Remediation Planning
    1. If remediation is required the facility will submit, within five business days, a plan for the remediation of each fixture on the contaminated riser.
      1. The facility will coordinate with the health district when the remediation will occur.
      2. The plan must include method(s) of remediation and the agreed-upon schedule of when remediation and sampling events are to occur.
      3. The schedule and plan will be submitted for approval before implementation.
    2. Recent facility history will be reviewed to determine if the remediation plan is appropriate for the facility or if other actions are needed.
    3. If the original riser requires remediation, the facility must decide within five business days if sampling or remediation of the remaining risers must also take place.
      1. If sampling will be done on the remaining risers, then a random selection of 1 percent of the rooms, along with a room on the distal end of each remaining riser/building, will be completed within 30 calendar days of the decision.
      2. The facility will use a third party ELITE certified laboratory for this sampling.
      3. All results must be shared with the health district upon receipt.
      4. The sampling may require observation by health district staff, which will be determined the Legionella Investigation Team. The results will be reviewed to determine if any additional remediation is required.
    4. If the facility decides to remediate the remaining risers, then the remediation must be conducted using the same approved process for the riser that required remediation.
      1. To ensure that the remediation was effective, 1 percent of the rooms along with a room on the distal end, must be sampled and tested for the presence of Legionella by a third party ELITE certified laboratory.
      2. This remediation, as well as post remediation, may require observation by health district staff, which will be determined by the Legionella Investigation Team. S.
      3. All post remediation results must be shared with the health district upon receipt.
      4. Additional remediation may be required depending upon the results.
    5. If it is determined, based on the laboratory results, that whole riser remediation is not required, then the facility will be instructed to remediate the system in a manner specified by the consultant. This remediation may not be supervised, but will require follow-up sampling of the fixture in the same manner as the initial positive sample.
  9. Remediation
    1. The sampling results and environmental findings must be reported to the facility in a formal letter. At this time, the facility management will be notified of additional sampling required within the facility.
    2. Remaining risers/buildings in the facility will be tested using 1 percent of all rooms served by that riser/hot water tank.
    3. The facility will submit a written plan of remediation for review and approval.
    4. After review, the health district will notify the facility whether or not the remediation plans have been approved.
    5. Health district staff will directly supervise all on-site remediation activities conducted by facility staff and/or consultants.
    6. The health district will determine the timeframe in which remediation activities will be conducted.
    7. The facility will coordinate remediation with the health district.
    8. Remediation will be conducted according to best industry practices outlined in ASHRAE Guideline 12-2000.
    9. All fixtures, including service and janitorial sinks, will be checked by facility staff to ensure proper chlorine and temperature levels are met, as determined by the facility’s consultant.
    10. The health district will verify that all facility staff members are conducting remediation activities as specified in the plan.
    11. The facility is responsible for all costs, including health district staff time, for remediation activities.
  10. Post-Remediation Follow-up Sampling
    1. Follow-up sampling will occur within seven calendar days of the completion of the riser’s remediation using the facility’s selected CDC ELITE-certified laboratory.
    2. One percent of all rooms, along with the distal room, served by the remediated riser will be randomly selected and tested.
    3. All fixtures on the remediated water system line(s), post-flush, within the randomly-selected room will be sampled.
    4. All sample results will be submitted to the health district.
    5. Any additional remediation will be determined using the protocols outlined in this document.
  11. Post Investigation Monitoring Schedule
    1. One percent of randomly sampled and distal rooms in the remediated riser of the facility will be tested on the following schedule:
      1. Bi-weekly for three sampling periods (six weeks).
      2. Monthly for three months.
      3. Quarterly for three quarters.
    2. Only one fixture per standard room needs to be sampled. If there are more than six fixtures in the room, then one sample per three fixtures will be taken.
    3. The facility will provide room numbers and sample locations to the health district two business days before sampling.
    4. Sample results will be provided to and analyzed by the health district using the protocols outlined in section V, paragraph C, item 7.
    5. Any additional remediation required will reset the monitoring schedule back to day one.

Contact Information

Phone: (702) 759-0677

Updated on: July 23, 2021

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