Construction Adjacent to a Transplant Unit, an Outdated Water Plan, and a Request to Sign Off
A 220-bed hospital begins a nine-month addition adjacent to the existing building. The construction site abuts the corridor serving an 18-bed hematopoietic stem cell transplant (HSCT) unit on the fourth floor, roughly 60 feet from the demolition. The infection control risk assessment (ICRA) was completed at design and scored as Class III. Three weeks into demolition, three HSCT patients develop invasive aspergillosis (Aspergillus fumigatus); two had been in the unit hallway during window seal replacement, and one had attended physical therapy on the second floor next to an active construction elevator. Separately, the hospital's cooling tower tested at 1,000 CFU/mL for Legionella two months ago, the water management plan has not been reviewed in four years, and a decorative lobby fountain has run throughout. The facilities director asks the infection preventionist to sign off confirming "the ICRA is done and the barrier is fine."
1. Evaluate the ICRA classification and the containment measures. What should have been in place, and how would you investigate the three cases?
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The classification is wrong. Demolition adjacent to an HSCT unit is the highest-risk category - Class IV, not Class III. HSCT recipients are profoundly neutropenic and the dominant risk is airborne mold generated by demolition. Class III assumes lower-risk populations and permits construction methods that are inadequate here.
What should have been in place:
- A sealed rigid barrier, not plastic sheeting, with the construction zone under negative pressure relative to the patient corridor, verified by a monitored differential and logged daily.
- HEPA-filtered negative air machines exhausting outside the building, with calculated air changes and filter certification on file.
- A construction anteroom with sticky/walk-off mats and contractor rules requiring passage through it; a dedicated construction elevator with a cleanable route, not one shared with patient transport.
- Window seal replacement scheduled around patient care, with patients relocated or work performed under containment. Two of the three cases were in the hallway during that work - that is the smoking gun.
Investigation: define a case (culture- or pathology-proven invasive aspergillosis with onset after demolition began), review all HSCT cultures, and type the Aspergillus isolates to assess clonality. Walk the barrier with facilities and check for the mundane failures: propped doors, bypassed pressure alarms, filters overdue for change, debris near air intakes, open windows. Routine air sampling is not a substitute for these observations. Aspergillus incubation of a few days to a couple of weeks fits the timing.
2. How do the cooling tower result and the decorative fountain fit in? What water management actions are required, and how do they relate to the aspergillosis cluster?
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Keep the two problems separate. Legionella is waterborne and not transmitted person-to-person; it does not explain invasive aspergillosis caused by construction dust. Conflating them will lead to the wrong remediation and will not stop the cluster.
However, the water program has its own serious failure. A cooling tower at 1,000 CFU/mL meets or exceeds the ASHRAE 188 action level for prompt corrective action, generally immediate online disinfection with documented verification, not a two-month-old note in a file. A water management plan unreviewed for four years fails the basic requirement for a team, a hazard analysis, control measures, monitoring, and periodic review and update.
Required actions:
- Convene the water management team; update the plan and the system inventory, including cooling towers, decorative water features, ice machines, and infrequently used outlets.
- Perform immediate disinfection of the implicated tower and retest; review drift and aerosol proximity to air intakes, especially near the HSCT unit.
- Shut off or remove the lobby fountain. Aerosol-generating water features have no place in a hospital serving immunocompromised patients.
- Assess the transplant unit's potable water: flushing of low-use fixtures, temperature control, and point-of-use 0.2-micron filters for high-risk patients during the remediation period.
- Add Legionella to the surveillance case-review list for hospital-onset pneumonia, including urinary antigen testing.
Document each action with dates, because "we looked into it" will not survive a survey.
3. How do you respond to the facilities director's sign-off request, and what improvement infrastructure would you put in place?
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Decline the framing, not the partnership. An ICRA is a living document with permits and milestones, not a design-phase form to be closed out. The infection preventionist cannot certify a barrier from an office; sign-off requires documented verification by a multidisciplinary team at defined checkpoints, and the IP must have explicit written authority to suspend work when containment fails.
Response in practice: state plainly that the barrier cannot be certified while three cases are under investigation, request the daily pressure logs and HEPA filter certification for the affected dates, and ask that window work adjacent to the unit halt pending review. Then propose the structure that prevents a repeat:
- A construction/ICRA team (IP, facilities, construction manager, unit nursing, safety, laboratory) meeting weekly and after any breach.
- A written permit-to-proceed for each phase, revocable on a failed inspection.
- Daily rounds with a standardized checklist covering barrier integrity, pressure differentials, anteroom compliance, debris, and traffic routes, with deficiencies corrected before work resumes the next day.
- Contractor education with signed acknowledgment at orientation.
Improvement metrics to report monthly: inspection compliance percentage, completeness of pressure logs, currency of HEPA certification, days from deficiency to correction, and HSCT invasive aspergillosis cases per 1,000 patient-days compared with the pre-construction baseline. Escalate the cluster to risk management and to the health department if required by state reporting rules, and coordinate any patient disclosure through administration rather than informally.