Chan Cheuk Chuen v. Pok Oi Hospital Operating As Pok Oi Hospital Tang Pui King Memorial College

HCPI 992/1999

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

PERSONAL INJURIES ACTION NO. 992 OF 1999

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BETWEEN

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Before: Hon A Cheung J in Court

Dates of Hearing: 9 to 12, 15 and 16 May 2006

Date of Judgment: 15 June 2006

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J U D G M E N T

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The claim

1.The plaintiff used to work as a school worker at Pok Oi Hospital Tang Pui King Memorial College in Yuen Long operated by Pok Oi Hospital.  He worked there for more than 9 years from September 1989 to December 1998.  From August 1989 to September 1996, his duties included working as a laboratory attendant.  He was also responsible for cleaning a boys’ toilet on the 4^th floor.  From September 1996 until May 1998, he worked as an attendant at the main entrance of the school.  He was also responsible for cleaning 3 classrooms, an art room, a computer room and a boys’ toilet.  In addition, on Saturdays, Sundays and school holidays, he stayed at school overnight as caretaker.

2.In this action against the school, the plaintiff claims that by reason of his repeated use of a “strong cleansing agent” comprising hydrochloric acid, commonly known as “漒(鏹)水” in Chinese, for toilet cleaning purposes over a prolonged period of time, he has developed a respiratory condition known as bronchiectasis, with a probable component of chronic bronchitis in his illness.  His condition was caused by, he alleges, his repeated exposure to the irritant fumes or vapour that billowed from the acid that he used for cleaning the toilet over the years.  His condition resulted in, in terms of symptoms, frequent cough with on and off haemoptysis (coughing up blood).

3.The plaintiff essentially claims that he has not received any proper instructions, warning or supervision from the school relating to the use of the acid for cleaning purposes.  No equipment, such as facial mask, was provided for his use.  Ventilation in the toilet was insufficient.

4.It is the plaintiff’s case that the repeated and prolonged use of hydrochloric acid for cleaning purposes caused his condition.  Alternatively, if that was not the case, such use certainly aggravated his condition.

5.He claims damages accordingly.

The employees’ compensation proceedings

6.Indeed, the plaintiff has also sought employees’ compensation from the school in DCEC 653/1998.  It is important to note that in those proceedings, the plaintiff did not proceed on the sole basis of his prolonged use of hydrochloric acid, but relied also on his work as a laboratory attendant at the school, in which job he had allegedly inhaled or otherwise come into contact with a variety of poisonous or irritant chemicals or chemical vapours.  He said that that resulted in his suffering from occupational asthma, a scheduled disease attracting compensation under Part III of the Employees Compensation Ordinance (Cap. 282) as well as bronchiectasis.  He claimed compensation for his occupational asthma.  Alternatively, he claimed that his bronchiectasis was the result of an “accident” at work, thus attracting payment of employees’ compensation under the general provisions in Part II of the Ordinance.

7.After trial (July 2000), his claim was dismissed by Deputy Judge Yuen, who found that the plaintiff was not suffering from occupational asthma.  He also held that the case put forward by the plaintiff did not constitute an “accident” at work, and therefore no compensation was payable under the general provisions in Part II of the Ordinance.  Depending on how one should read his judgment, the deputy judge seems also to have found that the plaintiff did not suffer from bronchiectasis, but rather chronic sinusitis which led to postnasal drip – thus the persistent cough, which was not caused by his duties at work.  The deputy judge thus dismissed the claim for employees’ compensation.  There was no appeal from that dismissal. 

Issue estoppel and the strike-out application

8.After the present action was commenced, the defendant duly took out an application to strike out the claim on the basis of issue estoppel.  The school relied on the apparent findings by the deputy judge in the employees’ compensation proceedings that the plaintiff had not been suffering from bronchiectasis, and that his condition was not caused by work.  The school was successful before the Registrar but the plaintiff’s appeal to Suffiad J in chambers was allowed.  The judge essentially took the view that the deputy judge did not make the findings that the school thought he had made – all the deputy judge decided was that the plaintiff was not suffering from occupational asthma and that there was no “accident” within the meaning of the Ordinance on the case presented by the plaintiff.  No positive finding regarding his true condition or the cause of it was made.

9.That notwithstanding, as Suffiad J’s judgment was only given in the context of a strike-out application, the question of issue estoppel remains a live issue in this action.

Sole reliance on exposure to hydrochloric acid

10.It is important to note that in the present case, the plaintiff says that his condition was solely caused by his use of hydrochloric acid for toilet cleaning purposes.  There is no longer any reliance on his (alleged) contact with or exposure to various chemicals and chemical vapours whilst working as a laboratory attendant at school for the causation or aggravation of his condition.

11.It thus becomes of crucial importance to find out, so far as causation is concerned, when he started using hydrochloric acid for toilet cleaning purposes.

The plaintiff’s evidence

12.It is common ground that the school started using hydrochloric acid for cleaning toilets in September 1994 when a new school worker started using it.  Soon thereafter, some other school workers followed suit.  Both sides agreed that hydrochloric acid is a common household cleansing agent.  It is also undisputed that in the summer of 1996, the plaintiff was instructed to use hydrochloric acid to clean a boys’ toilet at the school on two occasions – on each occasion six bottles of hydrochloric acid were used.  The plaintiff said the two incidents happened in July and August that year.  However, according to the documentary records as well as the witnesses called on behalf of the school (Mr Ng – a school teacher responsible for supervising the non-teaching staff including the school workers, and Madam Wong – the then supervisor of the school workers), the two incidents took place on or about 20 and 25 September 1996.  Having considered the entire evidence, I have no difficulty in preferring the latter version.

13.Anyway, the plaintiff’s oral evidence at trial was that prior to the two incidents that took place in the summer of 1996, he had already begun using hydrochloric acid for toilet cleaning purposes, albeit on a much smaller scale as compared with the two incidents in the summer of 1996 when 6 bottles of hydrochloric acid were used on each occasion to cleanse the extremely dirty toilet – it having been used by construction workers in connection with the construction of an extra storey at the school premises for about one year.  The plaintiff said that since about 1994, he had been using one to two bottles of hydrochloric acid (on each occasion) to clean the boys’ toilet from time to time.

14.With particular reference to the two occasions in the summer of 1996, the plaintiff said that when he poured the strong cleansing agent onto the urinals and over the floor of the toilet, yellow irritant fumes or vapour billowed from the acid and filled the toilet.  The ventilation fan in the toilet was not efficient in clearing the fumes or vapour.  He had to carry out his cleaning work although the toilet was filled with fumes or vapour because he was eager to complete the work as soon as possible.  He said he feared students might enter the toilet and get burned by the fuming acid.  While the plaintiff was working inside the toilet, he experienced excessive cough as well as skin irritation when he was sweating. 

15.The plaintiff said he suffered from on and off cough as a result of inhaling the irritant fumes or vapour.  There was initially scanty sputum, more in the morning and when lying down at night.  The sputum became more profuse and greenish-yellow in colour occasionally.  He said he had to consult doctors from time to time and took Chinese medicine almost continuously.  In about May 1995, he experienced more frequent cough with occasional blood stained sputum.  The plaintiff said he therefore made protests to the principal of the school (Mr Kwok) against the use of hydrochloric acid, but the principal insisted that the same be used for cleaning purposes.

16.The plaintiff also said that in addition to the two incidents in the summer of 1996 which he said took place in July and August, there was another occasion on 5 September 1996 when after cleaning the boys’ toilet with hydrochloric acid, he coughed up blood.  He sought medical treatment at Tuen Mun Hospital on the same day.  He also protested to the school principal about the use of hydrochloric acid, but to no avail.

17.The plaintiff said that thereafter he continued to use hydrochloric acid for toilet cleaning purposes.  He said on 16 October and 31 October 1997, after doing his cleaning work with hydrochloric acid, he experienced excessive coughing and he coughed up 3 to 4 cups or glasses of blood.  He was admitted to Tuen Mun Hospital for treatment at night and stayed in the hospital for several days.  He also said that on 31 October 1997, he coughed up blood again after cleaning work (using acid) and was again admitted to Tuen Mun Hospital for treatment.  However, according to the hospital record, his admission to Tuen Mun Hospital on that second occasion was to undergo an examination process known as bronchoscopy.

18.In late 1997, the hospital made a diagnosis of bronchiectasis, and the plaintiff duly told the principal about his condition, but nonetheless he was still required to clean the toilet with hydrochloric acid.

19.According to the plaintiff, there were yet another two occasions on 29 April 1998 and 11 May 1998 when after cleaning the toilet with acid, he coughed up blood.  From 12 May 1998, he was given sick leave which in fact continued until December 1999.  He said that in December 1998, he was forced by the school to quit his job.  He said that after December 1999, as he was unemployed and could not return to work anyway, he did not bother to obtain further sick leave from his treating doctors.

Other evidence

20.It is important, as I said, to determine whether prior to the two incidents in the summer of 1996, the plaintiff had been using hydrochloric acid for cleaning purposes.  This is because according to the known medical records and even according to the plaintiff’s own case, he started having frequent cough and sputum, and coughing up blood since 1995.  Since his present case is based solely on his exposure to the vapour or fumes of hydrochloric acid, if he had not started using hydrochloric acid prior to the two incidents in 1996 to any significant extent, his primary case would collapse by reason of causation, putting aside his alternative case on aggravation for the time being.

21.I have already outlined the plaintiff’s own oral evidence given at trial which referred to pre-summer 1996 use of hydrochloric acid to a significant extent.  He said at one stage of his oral evidence that he used at least 30 bottles of hydrochloric acid per year for cleaning purposes. He said the use caused or materially contributed to his condition, namely bronchiectasis, resulting in frequent cough, continuous production of sputum and his coughing up blood.

22.However, these allegations are not supported by contemporaneous documents.  According to a written record kept by Madam Wong, the then supervisor of the school workers, from 21 June 1996 up to end of 1998 (when the plaintiff left), the plaintiff had only been supplied with 12 bottles of hydrochloric acid for use on two occasions in the late summer of 1996, i.e. 20 and 25 September 1996, to cleanse the extremely dirty toilet which had been used by construction workers.  During the construction period of about one year, the plaintiff was not required to clean the boys’ toilet, which was (supposedly) cleaned by the construction workers themselves.  As a result, the toilet had become particularly messy.  The relevant entries in Madam Wong’s record were counter-signed by the plaintiff himself.  Indeed, it was also counter-signed by various other school workers who had obtained supply of hydrochloric acid from Madam Wong.  

23.Madam Wong said that the record prior to 21 June 1996 had been discarded (as a matter of routine).  She maintained that her record, insofar as it was still available, was a complete and accurate record.  Although hydrochloric acid was purchased by several workers on behalf of the school, every time the worker would claim reimbursement from her and she would make the relevant entry in the record to log the quantity of purchase, filled in the school voucher and claimed reimbursement from the school accounts lady.  She denied the plaintiff’s suggestion that there were occasions when he himself purchased hydrochloric acid for his own use in cleaning the toilet and on those occasions, while he claimed reimbursement from the school, no entry was made in Madam Wong’s record.  She said that unless the workman did not claim reimbursement (which possibility she discarded as most unlikely), all such purchases were entered by her in her record.  She also said that according to her recollection, the plaintiff had never purchased hydrochloric acid by himself and claimed reimbursement from her.  She also explained that hydrochloric acid was only used for deep cleansing of the toilets, which only took place about three times a year.  It was really up to the individual school worker to decide whether to use hydrochloric acid for cleaning purposes.  Besides hydrochloric acid, there were other cleansing agents available for use and they were also good for general cleaning purposes.  Hydrochloric acid was only used to remove persistent stains that were difficult to get rid of.

24.Despite his claim that Madam Wong’s record was not complete and there were occasions when he (as well as other school workers) simply bought hydrochloric acid by themselves for their own use at the toilets which would not result in any entries in Madam Wong’s record (they having claimed reimbursement from the school), I must say I have not been particularly impressed by the plaintiff’s assertion.  Rather, Madam Wong appeared to me to be an honest and credible witness.

25.But anyway, quite apart from Madam Wong’s evidence, it is of great significance to note that in the Form 2 filed for the purposes of employees’ compensation by the school dated 29 May 1998, there was no mention of the use of hydrochloric acid prior to the two occasions in the summer of 1996.  It is common ground that the relevant description of the matters under complaint set out in the Form 2 was supplied by the plaintiff himself.  The description reads:

“1989年至1996年在實驗室工作長期吸入化學葯品，1996年二次在校用鏹水洗厠所，97至98年在校用清潔劑令氣管擴張及出血。”

26.The description given was most succinct in setting out the plaintiff’s complaint: from 1989 to 1996, there was prolonged exposure to or inhalation of chemicals in the laboratories; in 1996, there were two occasions of use of hydrochloric acid for toilet cleaning; and in 97 to 98, the plaintiff used cleansing agents (which referred to general cleansing agents other than hydrochloric acid) at school.  It was alleged that all this led to bronchiectasis and haemoptysis.  The reference to use of hydrochloric acid was limited to the two occasions in the summer of 1996.

27.But not only that.  In a letter written by the office of Mr Albert Ho Chun Yan (a legislative councillor) to the school on behalf of the plaintiff dated 10 June 1998, it was alleged that:

“陳先生自一九九六年起在貴校任職實驗室清潔校工，負責清潔實驗工具及協助實驗室技術員工作。由於日常工作需經常接觸化學品，導致他因對此等物品敏感而經常咳嗽、嘔吐及流鼻血。至九六年中，陳先生亦須負責用鏹水清潔廁所。致使他的健康狀況進一步惡化。分別在去年十月十六日和本年四月廿九日，他兩次因為對化學品敏感引致氣管擴張及咳血而要到醫院治療。”

28.In other words, the reference to use of hydrochloric acid was again limited to mid-1996.

29.Furthermore, in the plaintiff’s application dated 7 September 1998 filed in the employees’ compensation proceedings, the plaintiff only referred to the use of hydrochloric acid for toilet cleaning purposes since 1996.  In a reply to request for further particulars filed in those proceedings dated 4 November 1998, the plaintiff again said that he was only asked to use hydrochloric acid to cleanse the toilet on three occasions, namely 5 September 1996, 16 October 1997 and 1 November 1997.  No pre-summer 1996 use of hydrochloric acid was ever mentioned.  (These employees’ compensation documents were disclosed and referred to only during final submission, but counsel for the plaintiff raised no objection to that course.)

30.In his witness statement dated 3 February 1999 filed in those employees’ compensation proceedings, the first incident of his being instructed to use hydrochloric acid for toilet cleaning purposes took place in August 1996.  Two other occasions of toilet cleaning were mentioned – 5 September 1996 and 16 October 1997.  Indeed in relation to the last occasion (16 October 1997), the plaintiff specifically said that what he used was bleach and a normal cleansing agent (“綠水”).  He did not refer to the use of hydrochloric acid on that occasion. 

31.All these documents quite clearly cast doubt on the plaintiff’s allegation that even prior to the two incidents in the summer of 1996, he had been using hydrochloric acid to a significant extent for toilet cleaning purposes.

32.On the other hand, I have not overlooked the fact that the plaintiff’s allegation of pre-summer 1996 use of hydrochloric acid started surfacing in mid-1999.  It appeared in the first report of Dr Yu Tak Sun dated 8 June 1999 – the plaintiff’s expert in the employees’ compensation proceedings as well as the present case.  In his statement of claim filed in the present action in April 2000, such pre-summer 1996 use was clearly pleaded.  Furthermore, despite what he had said or failed to say in his witness statement, during trial in the employees’ compensation proceedings (July 2000), the plaintiff did mention whilst giving oral evidence that there had been pre-1996 occasions of use of hydrochloric acid.

Discussion and findings of fact

33.I have considered the oral evidence as well as the documentary evidence before the Court and I have taken into account the demeanour of the respective witnesses.  I have, in short, borne the entirety of the evidence in mind.  I have particularly borne in mind that whilst I accept the accuracy and completeness of the still available record kept by Madam Wong, it did not relate to pre-June 96 supply of hydrochloric acid.  I have also borne specifically in mind the plaintiff’s known medical history over the years (including the timing of the appearance/disappearance of his symptoms and complaints such as coughing up blood).  Likewise, I have considered the fact that starting from 1999 onward, he has been maintaining a case of pre-summer 1996 use of hydrochloric acid.

34.Having borne everything in mind, I am afraid I am not satisfied by the evidence that there has been any or any significant use of hydrochloric acid by the plaintiff prior to the two incidents in the summer of 1996, which I find to have happened on or about 20 and 25 September 1996.  In other words, I do not accept the plaintiff’s assertion of any or any significant use of hydrochloric acid prior to those two occasions.  As regards any subsequent use of hydrochloric acid after those two occasions, again I am unable to accept the plaintiff’s assertion.  I find that apart from those two occasions, there has not been any or any significant use of hydrochloric acid by the plaintiff for toilet cleaning purposes at school.

35.In particular, the alleged use on 5 September 1996 which, the plaintiff claimed, resulted in his seeking medical treatment is not supported by any medical record.  In fact, according to the hospital’s record on 5 September 1996, the plaintiff went to the hospital for a hearing test, rather than to treat any coughing problem.

36.As regards the incident on 16 October 1997 which allegedly resulted in his admission to hospital, the relevant medical and hospital records did not mention any complaint of use of hydrochloric acid which led to the coughing and allegedly serious coughing up of blood.  Moreover, as pointed out above, according to the plaintiff’s own witness statement filed in the employees’ compensation proceedings, on that occasion (16 October 1997) no hydrochloric acid was used – rather he used bleach and a normal cleansing agent (“綠水”) for cleaning the toilet.

37.As regards the occasion on 31 October 1997, as indicated above, that admission was clearly for the purpose of carrying out a bronchoscopy.

38.All these alleged post-1996 uses of hydrochloric acid by the plaintiff are quite contradicted by Madam Wong’s record.

39.Madam Wong’s evidence on the record and the procedure of claiming reimbursement by the workers who helped the school to buy hydrochloric acid was essentially corroborated by the evidence of another school worker, Mr Tam, who gave evidence on behalf of the school at trial.

40.I have borne in mind the plaintiff’s explanations for all these discrepancies.  I do not find them to be particularly convincing.

41.Having heard both the plaintiff and Mr Kwok, principal of the school, I prefer the evidence of Mr Kwok and do not accept the allegations of the plaintiff that he had made repeated protests to the principal about the use of hydrochloric acid for toilet cleaning purposes.  I find it rather strange that a school worker would have taken, or would have found it necessary to take, the question of using hydrochloric acid for toilet cleaning purposes to the principal of the school “for protests”, by-passing his superiors and those responsible for non-teaching staff, like Madam Wong and Mr Ng.  I find the assertion that the principal would have wanted to ignore his protests and insisted on his using the acid for toilet cleaning – if indeed such protests had been made – equally puzzling.  Why should a principal be bothered with such a minor thing or be so insistent on a school worker’s using hydrochloric acid for toilet cleaning purposes at the risk of endangering his health?  In the normal course of events, one would expect the principal, if such protests had been made to him, to ask his staff members responsible for the matter about it.  Yet the unchallenged evidence of both Madam Wong and Mr Ng was that they never heard of any such protests until May 1998.  Likewise, one would expect these staff members to speak to the plaintiff about his complaints if they had been made aware of those protests.  But on the plaintiff’s own evidence, no such thing happened.

42.According to the documentary evidence as well as the oral evidence, the plaintiff never made any complaint to these people whose responsibilities included supervising his job in cleaning toilets.  Nor did he ever make any complaints to his fellow workers (including Mr Tam who gave evidence at trial), some of whom (including Mr Tam) also used hydrochloric acid for cleaning purpose from time to time – all without any problems or difficulties.

43.I have borne in mind the plaintiff’s explanations for all this.  I have not been impressed by his explanations.

44.I have taken into account the fact that apart from Madam Wong, all other witnesses called by the school still worked there at the time of trial.

45.As a whole, insofar as the factual evidence of the plaintiff differed from that given by Mr Kwok, Mr Ng, Madam Wong and Mr Tam (the fellow school worker), I prefer the evidence of these witnesses called by the defendant to that given by the plaintiff.

Conclusion on the case based on causation

46.Ultimately, I do not find myself in a position to believe the plaintiff’s story.  His claim, which is based solely on the use of hydrochloric acid for toilet cleaning purposes, must therefore fail, insofar as he says that the use caused his condition. His expert (Dr Yu) accepted that his condition, whatever it may be, was present back in 1995 when he started complaining about frequent cough and coughing up blood.

Case on aggravation

47.As far as the alternative case based on aggravation is concerned, it is necessary to consider the condition that the plaintiff has been suffering from.  The only pleaded case on aggravation is in relation to bronchiectasis.  There is no pleaded case on aggravation in relation to any other condition.  In other words, for the case based on aggravation to succeed, it is necessary for the plaintiff to prove that he has indeed been suffering from bronchiectasis.

Dr Yu’s evidence

48.To that end, the plaintiff relied on the evidence of Dr Yu, an eminent expert in occupational health and medicine.  Dr Yu took the view that the plaintiff is suffering from bronchiectasis; there is also a probable component of chronic bronchitis in his illness.  He based his diagnosis on the past medical and treatment history and records of the plaintiff, his own clinical examination and the CT scan results.  On page 16 of his first report compiled in 1999, he opined:

“Based on the information available to me, to a reasonable degree of medical certainty, there is a probable causal relationship between the examinee’s respiratory illness and his exposures to various chemicals at work.

The cause for patients with bronchiectasis is often difficult to document.  The symptoms often date from childhood and may be related to a single event.  The more well known associations are with respiratory infections of various types in childhood, especially whooping cough, measles and tuberculosis which were reported to be absent in this examinee.  Defects in host defence are less often reported causes and there was no evidence of such defects in this case.  Inflammatory disease/injury of the bronchial tree has also been documented to be associated with the subsequent occurrence of bronchiectasis.  A number of strong chemical irritants have been reported to give rise to the long-term complications of bronchiectasis and bronchiolitis obliterans in the medical literature …  As no other possible cause could be identified in the examinee, the bronchiectasis can be assumed to be a long-term complication of exposures to strong chemical irritants at work (sulphur dioxide, ammonia, chlorine, hydrogen chloride, etc.).

Chronic bronchitis is frequently associated with smoking but the examinee is a non-smoker.  On the other hand, it is well known that prolonged exposures to chemical irritants can result in irritant bronchitis (Barnhart S, 1994).  Prolonged exposures to acid vapours/fumes and other chemical irritants have probably contributed to the development of the symptoms of chronic bronchitis and the ventilatory and lung volume abnormalities.”

49.The report of Dr Yu reflected the case then put forward by the plaintiff – that his condition was caused by his prolonged exposure to a combination of chemicals that he came into contact with or inhaled whilst working as a laboratory attendant as well as the hydrochloric acid that he used in cleaning toilet.

50.In a report dated 17 August 2004 that he jointly wrote with the school’s expert (Dr Christopher Lai), Dr Yu reiterated his views as follows:

“The symptoms reported by Mr. Chan were suggestive of a medical diagnosis of bronchiectasis and the physical findings on examination of the chest suggested some local pathology present in the lower lobe of his left lung.  There was also a probable component of chronic bronchitis in his illness as was evidenced by the chronic symptoms of productive cough and the results from the pulmonary function examinations done in 1999.  Furthermore, High Resolution CT of the thorax by Dr. C.T. Wong of Yan Oi Diagnostic Radiology, Hospital Authority in December 1997 reported bronchiectatic changes and the most recent CT scan on 11 November 2003 also showed features of bronchiectasis, especially in the lower lobe of his left lung.

…

The cause for patients with bronchiectasis is often difficult to document.  The symptoms often date from childhood and may be related to a single event.  Well-known associations are with respiratory infections of various types in childhood, especially whooping cough, measles and tuberculosis, which were reported to be absent in this examinee.  Defects in host defence are less often reported causes and there was no evidence of such defects in this case.  Inflammatory disease/injury of the bronchial tree has also been documented to be associated with the subsequent occurrence of bronchiectasis.  A number of strong chemical irritants, with properties very similar to hydrogen chloride gas, have been reported to give rise to the long-term complication of bronchiectasis in the medical literature. …

The only positive risk factor for bronchiectasis that Mr. Chan had was an exposure to chemical respiratory irritants, including hydrogen chloride gas.  Hence, it was more likely than not that his bronchiectasis was a consequence of his past exposures to chemical irritants at work. …

Chronic bronchitis is frequently associated with smoking but the examinee was a non-smoker.  On the other hand, it is well documented that prolonged exposures to chemical irritants can result in irritant bronchitis.  Prolonged exposures to acid vapours/fumes and other chemical irritants at work had probably contributed to the development of the symptoms of chronic bronchitis in Mr. Chan.”

51.By and large, Dr Yu stuck to his opinion in his oral evidence given at trial.

Dr Lai’s evidence

52.The defendant’s expert at trial was Dr Christopher Lai, who, like Dr Yu, also gave expert evidence in the employees’ compensation proceedings.  Dr Lai is no doubt a distinguished respiratory expert.  He has written numerous academic publications on the human respiratory system and respiratory diseases.  During the course of evidence, he has repeatedly demonstrated his expert knowledge in matters relating to respiratory diseases.  He took the view that the plaintiff is not suffering from bronchiectasis.  Rather the most likely cause for his cough is chronic rhino-sinusitis with postnasal drip.  In his first report dated 16 June 1999, he wrote:

“Mr. Chan’s major medical complaints are frequent cough with repeated episodes of haemoptysis.  Although he was diagnosed as having bronchiectasis by Tuen Mun Hospital, there is, little, if any, evidence of this disease on HRCT thorax taken on 20^th May 1999.  Currently, HRCT thorax is considered as the gold standard diagnostic tool for bronchiectasis.  A review of the CT thorax taken at Tuen Mun Hospital 23^rd December 1997 also showed no definite evidence of bronchiectasis.  Thus, it is unlikely that Mr. Chan is suffering from clinically significant bronchiectasis.  The bronchial wall thickenings and parenchymal bands seen on HRCT probably represent scarrings, possibly as a result of previous inflammatory insults, e.g. infections.  In any case, they are of no major clinical significance, and in particular, should not have caused his respiratory symptoms.  In addition, the bulla present in the lower lobe of his left lung is also unlikely to account for his symptoms.

…

The chemicals that Mr. Chan alleged to have frequent contact during his employment at Pok Oi Hospital Tang Pui King Memorial College include mercury, mercury salts, formaldehyde and hydrochloric acid.  Of these, only the latter two substances may have the potential to cause the respiratory symptoms that Mr. Chan described.  Formaldehyde is a recognized cause of occupational asthma but Mr. Chan has no evidence of asthma at all, as pointed out above.  Acute heavy exposure to the fumes of hydrochloric acid may cause a condition known as bronchiolitis obliterans, however, the radiological and lung function changes do not show evidence of this disease.

The most likely cause for his cough is chronic rhino-sinusitis with postnasal drip.  This diagnosis is supported by his nasal symptoms and changes on HRCT paranasal sinuses.  The resultant cough may lead to mucosal damage in the airway, particularly the upper airways, and hence haemoptysis.”

53.In his joint report written together with Dr Yu in August 2004, Dr Lai maintained his views:

“Although the symptoms of chronic cough productive of purulent sputum are suggestive of bronchiectasis, it must be emphasised that the CT scans performed, including the latest one performed on 11 November 2003, did not show any convincing features of this disease other than scarrings.  The presence of crepitations in the left lower chest was consistent with the CT features of scarrings.  It is possible that he may have chronic bronchitis in view of his history of chronic cough with sputum.  However, other causes of chronic cough such as post-nasal drip due to chronic rhinosinusitis (CT paranasal sinuses in 1999 revealed appearance suggestive of inflammatory obstructive changes and he did admit to have nasal symptoms when I saw him then, though he denied any such symptoms when he was seen this year) and/or gastro-esophageal reflux (this may be asymptomatic other than causing chronic cough) may also be possible.

…

As indicated above, there is no convincing evidence that he is suffering from bronchiectasis.  However, even if he does, it is unlikely that this is related to previous exposure to hydrogen chloride gas or any chemical irritants.  While it is well known that such exposure can cause a condition called “bronchiolitis obliterans” – characterised by airflow obstruction on lung function testing -, there is no published literature that exposure to hydrogen chloride gas will cause bronchiectasis.  The localised area of scarrings in the lower lobe of left lung as shown on CT thorax (rather than diffuse changes), together with the absence of significant lung function impairment also argues against the notion that the history of exposure to hydrogen chloride is the cause for his present complaints.

…

While it is possible that he may have chronic bronchitis, which is a clinical diagnosis for someone with a productive cough for at least 3 months for 2 consecutive years, there may also be other possibilities for his alleged chronic cough …  The severity of his symptoms also appeared to be exaggerated as shown by the followings:

a. He could climb 3 floors at the same pace as the 2 examining doctors without any apparent distress, other than had a few coughs at the beginning (rather than at the end) of his exertion.  The coughs also appeared to be due to his forced ‘voluntary’ efforts; and

b. During physical examination, he didn’t cough while lying either on his back or on the right side, nor did he seem to be distressed by chest pain when he was asked to take deep breaths.

Even if he is suffering from chronic bronchitis, it is unlikely that this is a result of his work as a school labourer during the period of 1989 to 1998.  As explained in the report by Dr. D J Mabbott dated 11 June 1999 [neither side relied on that report], the intensity as well as the duration of exposure to such chemicals are unlikely to be sufficient for the development of chronic obstructive pulmonary disease (COPD).  The absence of similar respiratory complaints in other workers in the school also lends support to this notion.  It has to be emphasised that although tobacco smoke is the most important risk factor for the pathogenesis of COPD, exposure to indoor air pollutants from biomass fuel – for cooking and heating in poorly vented dwellings – is also considered as an important risk factor, especially in under-developed or developing countries.  In any case, the lack of respiratory function impairment as shown in the tests performed in 1999 also suggests that he only has trivial disease, even if he is considered having COPD.”

Discussion and findings of fact

54.I am of course aware that causation is a factual/jury question to be decided by the Court, rather than the experts.  The standard of proof is simply the balance of probabilities.  I am aware of the difference between the (higher) standard generally used by doctors to make diagnoses and the civil standard used by the courts to make findings and decide cases.

55.Having listened to the experts’ oral evidence and considered their expert reports as well as the literature that has been placed before the Court, I am not convinced on the civil standard, the burden being on the plaintiff, that he has been suffering from bronchiectasis.

56.The experts agreed that the CT scan result is important in diagnosing bronchiectasis.  There have been done three CT scans.  The first one was done in 1997, based on which the treating doctors at Tuen Mun Hospital first made the diagnosis of bronchiectasis.  None of these doctors were called to give evidence on their diagnosis.  Dr Yu accepted their diagnosis.  But he admitted that he had not seen the 1997 CT scan films.

57.On the other hand, Dr Lai had actually examined the 1997 CT scan films.  He disagreed with the diagnosis of bronchiectasis.  He heavily criticised the finding made by the radiologist at Tuen Mun Hospital that there were “generalize[d] mild bronchiectatic changes of cylindrical type noted in both lungs”.  He explained that bronchiectasis is a multifocal condition, affecting localised areas.  Thus, one seldom sees “generalize[d] changes”.  And if the condition should become so serious that it is generalised, it cannot be “mild”.

58.Dr Lai has actually examined the 1997 CT scan films and according to him, appearance of the so-called generalised mild bronchiectatic changes in both lungs was probably a case of “motion artefact” caused by the patient’s failure to hold his breath while undergoing the CT scan.

59.On the other hand, Dr Lai has commissioned a CT scan in 1999.  According to him, the CT scan revealed no bronchiectasis.  Rather there were scarring appearances in the right middle lobe and left lower lobe suggestive of pulmonary tuberculosis in the past.

60.I accept Dr Lai’s explanation that his failure to mention haemoptysis in the clinical history of the plaintiff supplied to the radiologist did not affect the radiologist’s opinion on the 1999 CT scan.  In any event, Dr Lai himself has seen the CT scan films and come to the same conclusion.

61.There was a third CT scan done in connection with the joint report of the two doctors.  I accept Dr Lai’s reading of the report of the radiologist who did the third CT scan in December 2003, namely that no convincing evidence of bronchiectasis was found.  I do not accept that the sentence “no gross change of bronchiectasis is noted” (my emphasis) used in the report is suggestive of the presence of some bronchiectatic changes nonetheless, as counsel for the plaintiff has suggested.

62.In any event, Dr Lai has examined the scan films and come to the conclusion that there was no convincing evidence of bronchiectasis.  In this regard, Dr Yu said that he noticed features of bronchiectasis from the scan films.  In cross-examination, he explained that what he saw was thickening of the bronchial wall.  However, that is, according to Dr Lai’s evidence and the literature, rather non-specific in terms of diagnosing the condition.

63.More importantly, Dr Lai made the point that since the condition of bronchiectasis is irreversible, if the plaintiff was really suffering from “generalize[d] mild bronchiectatic changes in both lungs” back in 1997, the subsequent CT scans ought to have shown a similar result, which was not the case.  In particular, even Dr Yu who had only seen the third CT scan films just managed to find features of bronchiectatic changes essentially in the lower lobe of the left lung, rather than any generalised or diffuse condition.

64.Both doctors agreed that the bronchoscopy carried out at Tuen Mun Hospital in October 1997 was of little use in diagnosing bronchiectasis (particularly in comparison with a CT scan).  Dr Lai was particularly critical of the comment made by the doctor who did the bronchoscopy that the plaintiff’s “airway calibre seems slightly larger than normal”.  Dr Lai said it was a particularly meaningless and irrelevant comment to make in the context of the test, for what is normal or not normal is really relative.  I agree with Dr Lai’s criticism.  I also agree that the diagnosis made by the doctor that what he had observed was “compatible with bronchiectasis” carried little weight in terms of diagnosis.

65.Rather, of greater significance is the fact that the doctor who carried out the bronchoscopy did not record any bleeding or accumulation of sputum on the bronchial walls.  (On the other hand, Dr Yu has pointed out in his evidence that the same doctor did not record any abnormality with the upper respiratory tract either.)

66.On balance, I prefer Dr Lai’s diagnosis of postnasal drip caused by the condition of chronic rhino-sinusitis.  The diagnosis is supported by the nasal symptoms of the plaintiff and the result of the second CT scan, which showed paranasal sinuses.  According to Dr Lai, who has had the advantage over Dr Yu in terms of treating patients on a daily basis, postnasal drip accounts for a majority of cases of frequent cough in Hong Kong.  The diagnosis made by Dr Lai is also consistent with a finding of chronic pharyngitis made at the Ear, Nose and Throat Department of Tuen Mun Hospital back in 1996.

67.As regards the entry made in the ENT records that there was no postnasal drip, Dr Lai explained that the entry was simply reflective of the lack of a specific complaint made by the patient.  He pointed out from literature that postnasal drip could be “silent”, without the patient being aware of it.  He also explained that the focus of the ENT expert at Tuen Mun Hospital at the time was to find out whether the plaintiff’s nasal bleeding condition was carcinomatous.  Dr Lai further said that in his 1999 examination of the plaintiff, he positively extracted medical history of symptoms of rhinitis from the plaintiff, i.e. episodes of runny-nose with postnasal drip and sneezing relating to infections since 1995.

68.Dr Lai said the resultant cough may lead to mucosal damage in the airways, particularly the upper airways, and thus haemoptysis.  He accepted in cross-examination that his diagnosis and explanation for the haemoptysis cannot stand together with the complaint of massive coughing up of blood, which allegedly took place on 16 October 1997, resulting in the plaintiff’s admission to Tuen Mun Hospital.  However, Dr Lai queried the plaintiff’s complaint of massive coughing up of blood.  He explained that such condition was not compatible with the doctor’s record on that occasion that the plaintiff’s chest was clear and there was no dyspnea.  Dr Lai also pointed out the possibility that a case of gastro-intestinal bleeding could mimic the so-called massive coughing up of blood.  In this regard, according to the medical records, the plaintiff did suffer from gastro-intestinal bleeding in April the same year.

69.But not only that.  The medical entries also recorded that the plaintiff had been suffering from haemoptysis for two weeks prior to admission, thus contradicting the plaintiff’s claim that after using hydrochloric acid to clean the toilet on the day in question (16 October 1997), he coughed up massive amounts of blood.

70.As for the x-ray taken in March 1996 suggesting that the paranasal sinuses appeared to be clear, Dr Lai explained that in this regard an x-ray examination is far less accurate than a CT scan (which was done in 1999 as mentioned above).

71.In any event, even if the plaintiff is really suffering from bronchiectasis as maintained by Dr Yu, I am not persuaded that that condition was caused by exposure to hydrochloric fumes or vapour.  This is an additional or alternative reason for my rejecting the plaintiff’s primary case based on causation (as opposed to aggravation).  In this regard, I accept Dr Lai’s expert evidence, which is well supported by literature both locally and internationally, that bronchiectasis is mostly idiopathic.

72.There is no direct literary support that exposure to hydrochloric acid could cause bronchiectasis.  The supposed analogy with exposure to sulphur mustard gas and alkylating agent used in chemical warfare that was relied on by Dr Yu is of doubtful value, particularly given that unlike sulphur mustard gas and alkylating agent, hydrochloric acid is water soluble.

73.More importantly, Dr Lai again pointed out quite convincingly that the well-known consequence of exposure to strong chemical irritants is bronchiolitis obliterans, which is not what the plaintiff is suffering from according to the tests carried out by Dr Lai.  There is simply no significant impairment of or changes in the plaintiff’s respiratory or lung functions.  According to Dr Lai, the case of exposure to chemical irritants causing bronchiectasis without affecting such functions is unknown.

74.Despite his long experience in occupational health, Dr Yu accepted that he had not heard of any case of hydrochloric acid-induced bronchiectasis in Hong Kong in the past twenty odd years.

75.Furthermore, the localised scarring in the plaintiff’s lung seen in the CT scan films andthe absence of significant lung function impairment suggest that the plaintiff’s condition (if he really is suffering from bronchiectasis) was caused not by exposure to chemical irritants but by a previous condition, such as pulmonary tuberculosis or other unknown causes.  On tuberculosis, both doctors agreed that a person could be suffering from pulmonary tuberculosis without knowing about it, thus resulting in a failure to extract any such medical history from the patient.

Conclusion on the plaintiff’s condition

76.In short, I find the alleged condition of bronchiectasis not proven.  Insofar as may be necessary, I find that the plaintiff has been suffering from postnasal drip caused by chronic rhino-sinusitis which resulted in his frequent cough and haemoptysis.

77.In those circumstances, as the plaintiff’s case on aggravation is limited to his suffering from bronchiectasis, his case must fail.  (There is no pleaded case on aggravation based on chronic rhino-sinusitis, and counsel for the plaintiff specifically disavowed any intention to run such a case at trial.)

78.Moreover, I would further find that even assuming that the plaintiff has been suffering from bronchiectasis, that condition was not caused by his exposure to the hydrochloric acid that he used for cleaning toilet.  That is an additional or alternative reason for rejecting the plaintiff’s primary case on causation.

79.As to chronic bronchitis mentioned by Dr Yu as a probable component of the plaintiff’s illness, I accept Dr Lai’s definition of the condition, i.e. continuous coughing for 3 months or more in a period of 2 consecutive years without any known cause.  In other words, if the cause is known, a diagnosis of chronic bronchitis is rather inapt, which is really a clinical diagnosis.  On the other hand, if the cause is unknown, so that such a diagnosis is made, the plaintiff’s case based on causation (as opposed to aggravation) must fail.

80.In the documents, there have been some mention of the plaintiff’s suffering from small airways disease.  I accept Dr Lai’s evidence that the cause of the disease is really unknown, but more importantly, it will not result in any impairment in respiratory functions or any other significant conditions on the part of the patient.  Put another way, it is really quite irrelevant to the present case.

Extent of aggravation

81.Lastly, I would add that so far as the plaintiff’s case on aggravation of his condition of bronchiectasis is concerned (assuming for the sake of discussion that he is really suffering from bronchiectasis), Dr Yu accepted that the degree of aggravation would very much depend on the quantity of exposure as well as the duration and frequency.  In the absence of any evidence regarding the actual content of the hydrochloric acid used for cleaning the toilet, Dr Yu (and indeed Dr Lai) both have had difficulty in quantifying, as it were, the degree of aggravation.  Dr Yu pointed to skin irritation as indicative of the concentration or purity of the hydrochloric acid used.  On the other hand, Dr Lai pointed to the absence of eye irritation as a counter-indication.

82.On the evidence adduced, I am unable to conclude that in case the plaintiff is really suffering from bronchiectasis, his exposure to hydrochloric acid has had the effect of aggravating his condition significantly.  Certainly, on the materials before me, I disagree that there has been caused any long-term aggravation of the plaintiff’s condition.  Taken to the highest, the aggravation is only temporary and limited in effect.

83.However, given my primary findings, I need not dwell further on the possible effect of aggravation.

Other issues 

84.For all these reasons, the plaintiff’s claim in the present action must fail.  That being the case, although I have heard arguments on breach of duty, issue estoppel and quantum, I do not intend to deal with them in any detail.  Suffice it to say, on breach of duty, I tend to agree with the submissions of counsel for the school, Mr Sham.  On issue estoppel, I tend to agree with the views of Suffiad J given in the strike-out appeal.  On quantum, I would, as a matter of completeness, quantify the plaintiff’s claim based on aggravation – if I had been with the plaintiff on this alternative claim – as follows.  I would award him $50,000 as damages for pain and suffering.  I would not award him damages for loss of earnings (past or future) because according to my findings, the only really significant incidents took place in September 1996.  That did not result in any loss of earnings on his part.  His subsequent complaints were, according to my findings, caused really by his condition rather than by any aggravation of such condition.

85.The degree of aggravation cannot be serious given that the only significant exposures to hydrochloric acid took place in September 1996 (i.e. the two occasions mentioned above), which did not lead to the plaintiff’s seeking medical treatment at hospital at all (the contrary assertion of the plaintiff is not accepted).  His 1997 admission to hospital was, on my findings, quite unrelated to the use of hydrochloric acid.

86.A sum of $1,000 would also be awarded to cover all incidental and miscellaneous items of loss.

Outcome

87.The plaintiff’s action is dismissed with costs to the defendant, to be taxed if not agreed – on a costs order nisi basis.  I also order legal aid taxation of the plaintiff’s own costs.

88.I thank counsel for their assistance.

Mr Chan Pak Kong, instructed by Messrs Au, Thong & Tsang, assigned by the Director of Legal Aid, for the plaintiff

Mr Walker Sham, instructed by Messrs Ip Kwan & Co., for the defendant