The above brief video clip shows hot steam exhaust near a bottle type cooling tower, that is a problem, heating up the cooling tower risks Legionella growth in the cooling tower and an explosive Legionella outbreak.
EMSD requires an independent auditor to inspect the cooling tower system every year.
After any prolonged shutdown, whether it is annual shutdown, holidays or the COVID-19 lockdown, buildings have idle water systems that are stagnating and risk fostering the growth of Legionella, the bacteria that causes Legionnaires’ Disease.
The BBC has reported three schools in the UK will delay opening because Legionella has been identified. Here is the link:
It is no surprise, the extended holiday / lockdown means the building water systems have been idle allowing water to stagnant, providing an environment for the growth of bacteria. If the water systems have not been flushed, the water system needs to be assessed.
During the lockdown thousands of workplaces, restaurants, offices, factories, and buildings are empty but remember that means the drainage systems may have dried out “U” traps, plumbing systems may have hot water heaters and potable water piping with stagnating water, whirlpool spas may have stagnant water, and building air conditioning cooling towers may contain stagnant condenser water.
Every risk and possibility cannot be listed here, therefore it is essential that the employer arrange for risk assessment to plan your start up.
Your plan needs to review and prepare an action plan to mitigate risks to ensure that all the systems are cleansed and checked BEFORE restarting, that means managers need advance notice, before for the opening date, to facilitate a safe start up procedure.
Management and managers should have contingency plans ready, just in case. However, the on-going public health emergency, recently labelled by WHO as a COVID19 pandemic, has exposed that organisations and employers are not prepared for change or business interruption. Even when organisations had some broad ideas, it was never formalised in a plan and never tested, only after the idea was tested was it revealed the idea did not work in practice.
In addition to the general confusion, caused by poor communications, random individuals post opinions and “advice” on social media, would you believe that an electrician is sending COVID19 pandemic advice!
In the context of the built environment, I am raising this issue because building operators, organisations and employers fail to plan for events that can be reasonably foreseen, such as fire. Organizing periodic fire drills to safely escape from a building in the event of a fire should be routine, but sadly its not.
Yet, there are countless tragedies every year, fatalities caused by a range of issues, locked fire escape doors trapping people inside buildings being one common issue. I have often been called to witness standby generator tests, which would not start! Therefore, in the event of an emergency those safety systems have no power!
COVID19 and Legionnaires Disease
It’s generally accepted that the number of Legionnaires Disease infections is under-reported, I predicted that the heightened public health surveillance for COVID19 would reveal an increasing number of Legionnaires Disease infections because both COVID19 and Legionella cause pneumonia.
To be perfectly blunt, its too late to try planning your escape from fire while trying to exit from a burning building, a decent manager will have a plan and considered difficult questions, or force a plan to be created, before a disaster strikes.
A Legionnaires Disease outbreak occurred in Hong Kong between 1st – 29th February 2020 with seventeen (17) patients diagnosed with no fatality reported by CHP.
The total number of cases reported by CHP is lower than 17 reported here because additional cases residing physically close (<1000m) to the Choi Hung MTR station and the Ngau Chi Wan market were excluded without any evidence of the distinction. Ngau Chi Wan market is a very popular wet market in the area, located on Clearwater Bay road, directly above the Choi Hung MTR station, it is high traffic area, used by people from the local estates, and the surrounding districts.
In total 15 cases were declared by CHP, twelve (12) male, and three (3) female, most were elderly residing near Choi Hung / Ping Shek Estate in Hong Kong, most with underlying disease.
At least two Legionnaires disease cases (refer to the table below, cases 12 and 13) were not counted as part of this cluster, yet both people reside nearby, approx. 1000m from buildings with confirmed cases, and well within the typical range of infection caused by cooling towers.
CHP also reported on 4 March 2020, specimens from two (2) more patients, that is eight (8) in total, match the samples from two Choi Hung MTR station cooling towers taken before the towers were disinfected (by implication sampled before 4 Feb. 2020). What is unclear, the initial 6 patients were reported on 14-2-2020, and three weeks later the additional pair were reported.
The CHP report on 4 March 2020 [link] that the Choi Hung MTR cooling towers have been disinfected and the water sampling test result (not provided) was stated to be lower than the action level. However, the tower installation date is not reported therefore it is unclear which COP would be relevant. Assuming CHP refers to the latest 2016 COP, it can be deduced that the Legionella sampling result was <10 cfu/mL and the Heterotrophic Colony count (also known as the plate count) sampling was <100 000 cfu/mL.
The CHP report concludes with a total of 27 cases for 2020, compared with 105 cases in 2019, which equates to 25% of cases in 2019 cases.
UPDATE 6 March 2020
EMSD.gov.hkissued a press release for its regular Legionella testing [link] on 6 March 2020 with routine and epidemiological investigation information, for the latter, in the attachment annex 2 [link] titled Building locations of fresh water cooling towers detected with total legionella count at/above upper threshold (1,000 cfu/ml) with nuisance notices issued under PHMSO, the annex states that the MTR Choi Hung Station had a nuisance notice issued showing total 1700 cfu/ml Legionella count (above the action level).
One late additional case was reported on 29-2-2020 involving a male admitted to hospital twice. Initially, the patient was admitted on 4 Feb. 2020, with pneumonia and discharged on 19 Feb. 2020, and then admitted again on 24 Feb. 2020 and Legionnaires Disease diagnosed. [CHP]
This additional case involved a male patient, aged 71 with underlying illnesses, who lives in Wong Shek House, Ping Shek Estate, Kwun Tong.
Given the initial onset date of this case and proximity, residing in Ping Shek Estate approx. 100m from the early cases involving Kam Shek House, this case must be classified as part of the Legionnaires’ Disease outbreak.
Although MTR cleaning tower maintenance/inspection was witnessed on 16-2-2020, CHP has not released any further details.
Two (2) more Legionnaires Disease infections were reported on 18-2-2020, bringing the total number of Hong Kong cases to twenty two (22) and sixteen (16) of those reside near Choi Hung. The new cases report by CHP include:
A male patient, aged 94 with underlying illness, who lives in Hung Shek House, Ping Shek Estate, Kwun Tong
A female patient, aged 52 with underlying illness, who lives in Block 2, 22 Wing Ting Road, Ngau Chi Wan (Fire Service Married Quarters)
The CHP report [link] lists fourteen (14) cases, attributing two cases (12 and 13) as residing in a different area, although physically close to the Choi Hung area, approx. 1000m from the buildings implicated in Choi Hung, Kowloon.
In earlier CHP reporting it’s noted that the Choi Hung MTR station has four cooling towers samples were taken before they were disinfected on 4 and 12 Feb 2020. And these match specimens from six (6) patients in the Choi Hung Area.
The novel coronavirus covid19 epidemic has increased awareness and heightened surveillance in Hong Kong. Since both diseases present with similar symptoms and both involve pneumonia, further Legionnaires Disease infections will be detected and diagnosed in the coming months.
legionella, legionnaires disease outbreak, Choi Hung, Ping Shek, cooling towers, Kowloon, pneumonia, Hong Kong
CHP reported one (1) additional Legionnaires Disease case on 17-2-2020, including the two nearby Kwun Tong cases, that brings the total number of cases to fourteen (14) so far in the Choi Hung and Ping Shek area. As reported by CHP all 14 cases involve persons with unspecified underlying illness.
The new case is a 72 year old male residing in Kam Shek House, Ping Shek Estate, the same building as previous case numbers 4, 5 and 8 (refer to map) reported more than ten days ago, that’s significant because the incubation period is normally 2-10 days.
Given the typical 2-10 day incubation period, this gentleman probably contracted the disease between 7 and 15 Feb. 2020, which is after the date CHP reported the Choi Hung MTR cooling towers were allegedly disinfected on the 4 Feb. 2020.
So far CHP has reported that six (6) cases match the specimens taken from the Choi Hung MTR station cooling towers before 4-2-2020, the exact date is not clear.
And MTR staff were witnessed working on one set of the Choi Hung MTR cooling towers on Sunday 16-2-2020, near the Leung Chung road / Ngau Chi Wan village sitting-out area (refer photo below)
Legionnaires Disease and novel coronavirus covid19 have similar presentations, considering the heightened surveillance and awareness surrounding the novel coronavirus covid19 it is inevitable that previously undiagnosed and unreported cases of Legionnaires Disease will be also be discovered.
Additional Hong Kong Legionnaires Disease Cases
In addition to the ongoing Choi Hung / Pink Shek outbreak, three (3) new cases were reported on 17-2-2020 residing in different areas of the city.
A male patient, aged 56 with underlying illnesses, who lives in 1H Sands Street, Central and Western District (Kennedy Town)
A male patient, aged 85 with underlying illnesses, who lives in Ma Tong Tsuen, Chuen Lung, Tsuen Wan;
A male patient, aged 52 with underlying illnesses, who lives in 7 Sau Fu Street, Yuen Long.
Outside Choi Hung, there are six (6) cases in total with no apparent connection to the Choi Hung Outbreak. However, it must be said that the CHP reporting is vague.
legionella, legionnaires disease outbreak, Choi Hung, Ping Shek, cooling towers, Kowloon, pneumonia, Hong Kong
There are countless poorly informed commentators that promulgate the myth that Legionnaires Disease is only warm-weather / summer time disease, it’s not, and never has been.
It’s winter in Hong Kong and we have an ongoing Legionnaires Disease Outbreak with patients admitted between 1 Feb. 2020 – 14 Feb. 2020 so far.
Lets assuming ten (10) day incubation period, what was the weather during that period of time? The Hong Kong Observatory records daily weather data, and the following minimum and maximum air temperatures were in recorded at Kwun Tong, the nearest weather station to the outbreak:
22 Jan 2020 between 16.9 C and 24.4 deg C
23 Jan 2020 between 19.8 C and 25.5 deg C
24 Jan 2020 between 18.4 C and 22.6 deg C
25 Jan 2020 between 17.9 C and 21.9 deg C
26 Jan 2020 between 12.2 C and 20.1 deg C
27 Jan 2020 between 9.8 C and 16.9 deg C
28 Jan 2020 between 9.9 C and 16.4 deg C
29 Jan 2020 between 10.1 C and 17.9 deg C
30 Jan 2020 between 10.3 C and 17.6 deg C
31 Jan 2020 between 11.7 C and 17.8 deg C
1 Feb 2020 between 13.4 and 17.7 deg C
2 Feb 2020 between 15.0 and 17.7 deg C
The HKO data shows the typical range of wintertime temperatures experienced during the cold weather season in Hong Kong.
In conclusion, the evidence demonstrates that during cold weather Legionnaires Disease outbreaks do occur, contrary to literature this disease is NOT limited to warmer climate conditions, and during the winter Legionnaires Disease cases, clusters, and outbreaks may occur.