1 SUMMARY DECISION NO. 1906/99 Mesothelioma; Exposure (asbestos); Apportionment (occupational disease). The worker appealed a decision of the Appeals Resolution Officer, which found that the worker had mesothelioma but denied entitlement to benefits for the disease on the grounds that evidence did not support exposure to asbestos in the workplace. Medical evidence supported the conclusion that the worker had malignant epithelial mesothelioma. Asbestos is the only known causal agent in the development of mesothelioma and there is no known dose threshold. The median latency period for development of mesothelioma according to the Royal Commission on asbestos was about 25 years. The latency period was usually between 25 and 40 years, and rarely less than 20 years. The worker had a varied career starting at age 16 in He exhibited the first signs of mesothelioma in The worker was employed in three occupations where he could have been exposed to asbestos. He was employed with the accident employer as a machinist from 1968 to 1969 and again from 1973 to Asbestos was present in various locations with this employer. He was employed with another employer where asbestos was used as insulation from 1969 to He was employed as a heavy equipment operator for a third employer from 1972 to 1977 where he was transporting materials that may have contained asbestos. The employment with all three of these employers was consistent with the latency period for development of mesothelioma. The Panel concluded that the worker had entitlement for mesothelioma related to exposure in these three different industries. The appeal was allowed. The Board was directed to apportion costs of the claim equally between the three classifications. [20 pages] DECIDED BY: Sutherland; Beattie; Robb DATE: 14/02/2001 NUMBER OF PAGES: [20 pages] ACT: WCA
2 2001 ONWSIAT 406 WORKPLACE SAFETY AND INSURANCE APPEALS TRIBUNAL DECISION NO. 1906/99  This appeal was heard in Erin on October 27, 1999, by a Tribunal Panel consisting of: S.J. Sutherland: Vice-Chair, C.J. Robb : Member representative of employers, D.B. Beattie : Member representative of workers. THE APPEAL PROCEEDINGS  The worker appealed from the decision of the Appeals Resolution Officer, R. Sheridan, dated March 15, In this decision, the Appeals Resolution Officer accepted that the worker had mesothelioma but denied the worker initial entitlement to benefits for this disease on the ground that there was no objective evidence to confirm the worker s assertion that he was exposed to asbestos in the workplace.  The employer has cross-appealed the Appeals Resolution Officer s finding that the worker has mesothelioma. In the employer s submissions, the medical evidence does not support this diagnosis.  The worker appeared and was represented by J. Herman, of the Office of the Worker Adviser.  The employer appeared in the person of its occupational health nurse, and was represented by R. Boswell, a lawyer with Hicks, Morley, Hamilton, Stewart, Storie.  The worker s wife observed the proceedings.  In a letter dated August 6, 1999, Mr. Boswell argued that, if the worker was granted initial entitlement to benefits, it was the employer s view that the worker s exposure to airborne asbestos occurred when he worked for other employers. Mr. Boswell cited a report dated July 14, 1999, prepared by an Industrial Hygienist, in which the Industrial Hygienist identified a particular workplace where it was likely that the worker had asbestos exposure.  On August 11, 1999, D. Castrucci, of the Tribunal Counsel Office, advised the representatives that she had contacted the Workplace Safety and Insurance Board and had ascertained that the employer referred to by the Industrial Hygienist and Mr. Boswell has closed.  On October 28, 1999, the Panel instructed E. Smith, of the Tribunal Counsel Office, to obtain medical information that was referred to in the file and to send this information, together with all the evidence that was before the Panel members to an assessor chosen by the Tribunal. The Panel set out our findings of fact in our memorandum to Ms. Smith, as well as the questions that we wanted the assessor to answer.
3 Page: 2 Decision No. 1906/99  Two assessors reports were obtained by the Tribunal Counsel Office. The first was received on March 20, 2000, and the second on June 15,  The worker passed away on May 3,  K. Lovely, who replaced Mr. Herman as the worker s representative, stated on June 28, 2000, that he had no further submissions to make. Mr. Boswell s submissions were dated July 12, THE EVIDENCE  The Panel had the following written materials before it: Exhibit #1: Case Record; Exhibit #2: Addendum #1; Exhibit #3: Addendum #2; Exhibit #4: the Vice-Chair Registrar s certification that the file is hearing ready; and Exhibit #5: a letter dated October 7, 1999, from the Tribunal Call Centre to Mr. Herman, with attachments.  The worker gave evidence under oath at the October 27, 1999 hearing. Messrs. Herman and Boswell made brief opening remarks and closing submissions.  The Panel members considered the above evidence, as well as that collected after the hearing, in coming to our conclusions in this appeal. THE ISSUES  The worker is seeking recognition that his mesothelioma resulted from exposure to asbestos in the workplace, and all the benefits that would flow from such a decision.  The employer asks the Tribunal to find that the worker does not have mesothelioma. PRELIMINARY MATTERS  Mr. Herman stated that a report he had previously submitted, dated September 16, 1999, from the Occupational Health Clinic for Ontario Workers Inc. contained an error. He had copies of the revised report. Mr. Boswell reviewed the revision and had no objection to the Panel receiving the revised document into evidence.
4 Page: 3 Decision No. 1906/99 THE REASONS (i) Background  The worker was 54 years old at the time of the hearing. He started working at the age of 16 and had a varied career as an upholsterer (1962 to 1963); a tannery worker (1963 to 1964); a carpenter (1964 to 1966); an assembler of air conditioners and household electrical appliances and a stock-room clerk (1969 to 1971); a truck driver for various companies (1971 to 1972, 1979 to 1991); a heavy equipment operator (1972 to 1977); and a snow plow operator (part-time from 1982 to 1989). The worker was self-employed as a builder of decks and fences from 1991 to 1994, and as a long distance truck driver, from 1994 to He worked for the employer, as a machinist, between August 16, 1966 and February 18, 1969, between May 20, 1969, and November 2, 1969, and again from November 5, 1973, until May 3, The employer is a corporation that manufactures, assembles, repairs, and overhauls aircraft jet engines and components.  The worker smoked about 10 cigarettes per day from about 1977 to December 1997, and three or four cigarettes per week after that. The worker had gastric ulcer surgery in 1973 and transitional cell bladder cancer that was treated with laser ablation about There was no other family history of malignancy.  About the middle of 1997, the worker began to experience shortness of breath with physical exertion. He had a fever, chills, and sweats in October, and pneumonia in November He stopped working in November 1997, on the advice of his family physician. He tried to return to work as a truck driver, in March or April 1998, but was unable to continue because of pain in his chest.  The worker s ability to breathe gradually got worse. On December 4, 1997, Dr. G. Hollinger, a specialist in pulmonary and internal medicine, opined that it was likely that the worker had a pleural malignancy.  On May 1, 1998, the worker wrote the Board and asked that a claim be established for mesothelioma. The Senior Claims Adjudicator ordered an investigation. The investigation took place in June The Senior Claims Adjudicator denied the worker s claim on September 29, The worker appealed and the Appeals Resolution Officer upheld the Senior Claims Adjudicator s decision.  The worker has appealed to the Tribunal. (ii) The worker s testimony  The worker verified that he worked for the employer between 1966 and 1969 and again in 1973 and He testified that he only worked in one building on the employer s premises. He did not work directly with asbestos and was not aware that there was any asbestos in the plant at the time. He did not know what asbestos looked like and could not have identified it if he had seen it. He has since found out that the employer had asbestos removed from the facility in the 1980s. He thought that this asbestos was in the ceiling and in pipe elbows.
5 Page: 4 Decision No. 1906/99  The worker operated machines for the employer. There were welders on one side of him. On another, the parts that were cut on his machine were hand finished. There was a laboratory nearby but the worker did not know what activities were carried out in the laboratory. There was a spin test table about 20 feet from his workstation. At this location, parts were frozen, heated, and checked for cracks. There was a heat treat room about 200 feet from his work location. In the heat treat room, painted parts made of titanium and high strength steel were baked in a furnace. There was a steel insulated garage door on the room but the worker never saw the door closed. The worker believed that asbestos was used as insulating material on the furnace. The people working in this area wore white coveralls and a white hat. They did not change their clothes when they took breaks. Some went for lunch at the same time as he did. Lunch was in shifts because the lunch room was not large enough to accommodate all the workers. The worker never worked in this area, but he occasionally walked through it as a shortcut to the lunch room.  The worker testified that there was a ventilation system in the ceiling that drew the air out of the plant. There were also heating and air conditioning systems, both of which utilized ceiling fans. There were pipes in the ceiling and some pipes that ran down from the ceiling. The pipes carried steam because the plant had a boiler. He speculated that there was probably a cold return as well. The pipes were about 8 in. across and about 30 feet above his head. These pipes and the ceiling were maintained and repaired as required. These activities were accomplished by using a manlift to get the repair man or maintenance man to the area requiring work. The worker said that this work was done during regular working hours and he carried on with his job while these workers were working overhead. As he recalled, pipes in his area were fixed on a weekly basis. In addition, there was always somebody working overhead on lights, fans, electrical conduit, etc.  Mr. Herman reviewed with the worker documents provided by the employer that indicated the locations of asbestos in its facility. The worker did not know the location of most of the identified areas. The documents showed that there was asbestos in the offices and conference rooms in the building where he worked. The worker testified that he never worked in these locations.  Mr. Herman reviewed the worker s employment history with him. The worker stated that when he did upholstery work, he used a woven straw matting. He thought this was fibre and not asbestos. He testified that his job duties included putting springs on frames, attaching the matting, padding, and finishing the item. He never cut material for the upholstery work. He was unable to identify any potential asbestos exposure in this job.  The worker testified that the employer for whom he worked between 1969 and 1971 used asbestos in the insulation of small appliances, in particular toasters and irons. However, he did not work as an assembler of these appliances. He put covers on air conditioners and insulated them with fibreglass. He was certain that the insulation was fibreglass and said that this came pre-cut.  The worker mentioned that he was promoted to the stock room and in this job he delivered boxes and parts to the lines on which toasters and irons were assembled. He estimated that he walked through these areas 20 or 30 times per day. He also owned a toaster and an iron that was made by this manufacturer.
6 Page: 5 Decision No. 1906/99  The worker testified that he did various jobs for a number of construction companies. These jobs included driving trucks and heavy equipment, using a hand shovel, and working on cement forming. He began working on a site as soon as it was surveyed. He ate his meals in the buildings on the construction sites. He stated that developers would buy property, demolish the old buildings and re-grade the lot. His job was to haul away the demolition material. The material usually consisted of the remains of old houses, farmhouses, and barns. As far as he could recall, he never hauled the remains of industrial or commercial buildings.  Mr. Herman asked the worker about his job activities with the construction company for whom he worked from 1972 until The worker answered that he drove heavy equipment such as backhoes to excavate foundations and he hauled both old and new sewer pipes. He stated that this employer did a lot of work on storm and sanitary sewers. The pipe was old, decaying, and collapsing. There was very little hand work on this job and he never used a hand saw to cut the pipes. The pipe was picked up by machine and put in his truck. He would take it to the disposal location and dump it. He described the pipes as generally being mucky and not dusty.  Mr. Boswell drew the worker s attention to a report written by J. Oudyk, an occupational hygienist, on July 13, In this report, Mr. Oudyk described the pipe as being made of Transite. Mr. Boswell asked the worker if he told Mr. Oudyk this. The worker answered that he did not know what the product was. All he knew was that it was old concrete pipe. He believed that about half his work over the five years that he was employed by this contractor involved the removal of this pipe. He was also involved in the demolition of curbs, road beds, and bridges at this time.  The worker testified that he never wore asbestos gloves, as far as he was aware. He occasionally changed the brakes on his own vehicles but he never did this professionally and he never ground brake pads. As far as he knew, he never lived in a house that had asbestos insulation.  In response to questions from Mr. Boswell, the worker said that he had had his chest drained since the Appeals Resolution Officer s hearing. This procedure took place in June 1999 and the doctor did a biopsy at the same time. He had not seen Drs. LeBlanc or Patel 1 in a year because there was nothing that they could do for him and they did not feel that a trip to Hamilton would be beneficial. He recalled that a doctor had explained to him that it might be necessary to have an open lung biopsy. He stated that he refused this procedure because he had been advised that there was a 70% to 80% that it would increase the spread of his cancer and the doctors could not confirm that this procedure would result in a better diagnosis. He had a bladder problem in This turned out to be a ruptured blood vessel and was not a malignant tumor. He saw the surgeon who treated him, in December 1998, and was advised that the condition was 100% cured. 1 Doctors who treated the worker at a regional cancer centre.
7 Page: 6 Decision No. 1906/99  The worker testified that he has never visited or lived in Turkey. He has had no radiation therapy. He has never had tuberculosis. The description of the worker s various jobs and potential exposures, as set out by Mr. Oudyk in his report dated July 13, 1999, was accurate. (iii) The medical evidence  The first medical report on the file is a consultation report dated November 13, 1997, and prepared by Dr. L.A. Keevil, a radiologist. Dr. Keevil reported that he had x-rayed the worker s chest. There was evidence of fluid and pleural thickening in the worker s right lung base. Dr. Keevil opined that these could have resulted from either an inflammatory process or a malignant one.  On November 18, 1997, Dr. J.P. Rahal, a radiologist performed a lung scan on the worker. Dr. Rahal noted the right pleural effusion but opined that the lung scan was within normal limits although it was possible that the worker had a pulmonary embolus.  On November 18, 1997, Dr. L. Friedman, a radiologist, reported that he had conducted an ultrasound and found no evidence of a venous thrombosis. Dr. Friedman also took x-rays of the worker s chest and noted the worker s pleural effusion, but no other abnormalities.  The worker consulted Dr. C.G. Hollinger, a specialist in pulmonary and internal medicine, on November 27, Dr. Hollinger ordered that a sample of the fluid in the worker s chest be aspirated. This procedure was conducted by Dr. Friedman on November 28,  Dr. Hollinger reported, on December 4, 1997, that the worker appears to have a pleural malignancy. He ordered a CAT scan and a bone scan. Dr. D. James, a specialist in nuclear medicine, reported on December 15, 1997, that the results of these procedures were normal.  On December 18, 1997, Dr. Hollinger stated that I think the likelihood that this is not a malignancy is very low. He ordered an intercostal block to control the worker s pain.  Dr. K.S. Billing, an anaesthetist, injected seven intercostal nerves on December 19,  Dr. A.J. Martin, the worker s family physician, reported on December 5, 1997: Right basal effusion. Soft tissue lesions as described along the right aspect of the lower sternum extending into the pleural cavity. These remain nonspecific but the possibility of pleural metastatic lesions cannot be completely excluded.  Dr. Hollinger carried out a pleural biopsy on January 8,1998. The pathology report was prepared by Dr. E.T. Ling, a pathologist, on January 8, Dr. Ling reported: Sections of all four biopsies show small fragments of skeletal muscle fibres, parietal pleural fibrous tissues and small clusters of mesothelial cells. No malignancy is noted. This material, together with the cytology of the pleural fluid will be sent for a second opinion in view of the previous clinical history and the CAT scan findings.  The cytology report was prepared by Dr. J. Samuel, a cytologist. Dr. Samuel s opinion was that the specimen was suspicious for malignancy.
8 Page: 7 Decision No. 1906/99  The fluid from the worker s lung was also tested for tuberculosis on January 15,1998. This test was negative.  The worker had an x-ray of his chest on January 21, Dr. C.A. Morrison, a radiologist, reported: There is pleural thickening and/or fluid seen in the inferior portion of the right lung. Conceivably this could represent a mesothelioma, although the appearance is nonspecific. There is no other evidence of asbestos exposure. The other abnormality I see is possible paratracheal adenopathy. Has a CT scan been done?  Dr. J.M. Kay, a professor of pathology at McMaster University, reviewed the medical evidence, including 17 microscope slides, the surgical pathology report, and two cytology reports, on January 21,1998. Dr. Kay reported: The pleural biopsy and the two pleural fluid contain atypical mesothelial cells which are solitary and in small clusters. I am convinced that these cells are mesothelial rather than adenocarcinomatous because the majority are immu noreactive for calretinin which is a marker for mesothelium. WT1 our other marker for mesothelium is negative. The cells are also negative for mucin, CEA and Leu M1. Thus, the differential diagnosis lies between reactive mesothelial cells and mesothelioma. I favour reactive mesothelial cells because the cells are negative for P53 and only a small minority are positive for EMA.  The worker was referred to a Regional Cancer Centre where he consulted Drs. L. LeBlanc and M. Patel, both of whom are radiation oncologists, on January 21,1998. These doctors explained the difficulty in obtaining a definitive diagnosis and discussed the worker s options with him and his wife.  The slides and specimens examined by Dr. Kay were reviewed by Dr. G.L. Frank on January 28,1998. Dr. Frank agreed with Dr. Kay that the worker had reactive mesothelial cells and not a malignancy.  Dr. Keevil x-rayed the worker s chest on March 5, He described the pleural effusion as being moderately large and said that the worker s lung field was otherwise clear.  Dr. Hollinger examined the worker on May 7, The worker was complaining of pain in his left arm and a swollen, tender left elbow. Dr. Hollinger ordered further testing. The results of this testing were not in the materials before the Panel.  On August 27, 1998, Dr. D. Daya, a professor of pathology at McMaster University, reviewed biopsy materials. Dr. Daya concluded: You are quite right in suspecting a mesothelioma in this case. The biopsy shows an infiltrative tumour composed of malignant cells arranged in cords and clusters, focally invading the subjacent striated muscle. Immunohistochemistry certainly favors a diagnosis of malignant mesothelioma over a metastatic adenocarcinoma (calretinin positive, LeuM1, CEA and B72.3 negative).  Dr. Daya s diagnosis was malignant mesothelioma.
9 Page: 8 Decision No. 1906/99  The Claims Adjudicator asked for a medical opinion with respect to the cause of the worker s mesothelioma. Dr. J. Roos, a Board respirologist, answered on September 22, Dr. Roos concluded: Probable and sufficient asbestos exposure for the development of malignant mesothelioma has not been shown for this worker.  On August 31, 1999, Mr. Herman wrote two employees of the Occupational Health Clinics for Ontario Workers Inc., M. Tew, an Occupational Health Nurse, and Dr. K. Burgess, an occupational health physician, and asked whether the diagnosis of mesothelioma had been histopathologically confirmed; if it had not been histopathologically confirmed, how accurate the diagnosis was; and the likelihood that the worker s lung condition had been caused by exposure to asbestos at work. Dr. Burgess replied on September 16, He reviewed Dr. Daya s report of August 27, 1999, and concluded that the diagnosis of mesothelioma had been histopathologically confirmed. He was of the view that it was also clear from the clinical data that the worker had mesothelioma. Dr. Burgess went on to say: (iv) In summary, the patient has a type of cancer which is widely accepted to be caused in the majority of cases by an exposure to asbestos. He had exposure to asbestos. The exposure was not heavy, however, there is no known safe level of asbestos with respect to the outcome of mesothelioma. It is certainly more likely than not that his asbestos exposure caused his cancer. The evidence related to the worker s exposure to asbestos  The employer provided the Board with copies of memoranda related to its use of asbestos. The first memorandum was dated April 28, 1980, and was written by the plant engineering manager (the manager). The manager stated that he had checked the original building drawings and specifications and determined that asbestos was used in parts of four buildings. This memorandum showed that the building in which the worker was employed had asbestos in the ceiling of the main lobby and in the ceilings in three offices and a conference room.  On March 28, 1983, the manager listed the following places, in addition to those in his earlier memorandum, where asbestos could be found 2 : the gaskets on duct cleanout covers; insulation on piping and equipment (pipe fittings; valves, strainers, water meters, and domestic hot water tanks); furnaces and drying ovens (gaskets, asbestos rope, insulation padding); Lanly oven; asbestos boards (for putting parts on); packing used in valves and pumps; asbestos blanket at metal spray unit; welding blankets used by maintenance department asbestos cement pipe; 2 The Panel has listed only those areas in which the worker might have been employed.
10 Page: 9 Decision No. 1906/99 asbestos gloves (drying ovens and furnaces); and asbestos covered electrical wiring.  The employer provided a research report dated June 6, 1986, titled: An Assessment of Airborne Fibre Concentrations at [the employer] for [the employer]. The summary of that report said: Ten samples of airborne particulate/fibrous matter were collected at the [employer s] and analyzed for fibres (asbestos) using the PCM method specified in the Ministry of Labour s code for measuring asbestos. As the analytical method used is not specific for asbestos, all fibres collected were assumed to be of the chrysotile asbestos type. The airborne fibre concentrations ranged from non-detectable to fibres (> 5 µm in length)/cc of air. All results, therefore, were significantly below the current permissible MOL TWAEC of 1.0 fibre/cc of air, for chrysotile asbestos.  The employer also provided a copy of an undated document titled Asbestos Use And Control Program. The writer of this document said: From spot check inspection throughout the facility, it is concluded that: 2.1 All straight run piping used fiberglass insulation or corrugated cardboard material. 2.2 All elbows, tees, valves, etc., contain asbestos material. 2.3 Domestic hot water tanks contained asbestos. 2.4 Some duct work and fans have asbestos covering. 2.5 All piping, walls in service center and rooms contained asbestos. 2.6 All boiler and equipment units have asbestos covering. 2.7 Some electric and/or pit furnaces may have asbestos in wiring and brick work. 2.8 Asbestos blankets. 2.9 Asbestos gloves Hoist brake pads and pump packings.  The writer concluded that a control program was required where changes or damage had occurred to piping or valves. A control program was required to deal with the domestic hot water tanks in the service centres. A control program was required in service centre A.  On July 2, 1998, the employer s manager, health and safety (the health and safety manager) advised the Board that the employer never used asbestos for any purpose except insulation. The health and safety manager reviewed the worker s personnel records and stated that the worker never worked in one of the areas that the worker described to the Claims Investigator (the blast furnace). The health and safety manager said that he had interviewed eight long-term employees with respect to the other area described by the worker (the spin test). None of these employees recalled asbestos being used in this operation. From personal knowledge, the health safety manager stated that there was no heat source such as the worker described in this operation. The health and safety manager could not find evidence of asbestos insulation on piping and said that fibreglass or corrugated cardboard had been used. Finally, the health and safety manager stated: There is no record or history of any one of the thousands of people who have been employed in
11 Page: 10 Decision No. 1906/99 this facility over the last fifty years having any medical problem which was related to asbestos exposure.  On June 26,1998, the Claims Adjudicator asked a Board Occupational Hygienist to review the worker s file and provide an opinion with respect to his likely exposure to asbestos. Dr. H. Kabir answered on August 6,1998. Dr. Kabir pointed out that asbestos was widely used as insulation material in Ontario in the early 1970s and earlier. He was of the view that asbestos insulation on the ceiling was of no consequence because it would not have been disturbed by the worker s activities. In his opinion, it seemed reasonable to conclude that there was asbestos in sheets and the process pipes leading to and from the machine that claimant operated. Dr. Kabir stated: As far as the level, duration of exposure and latency are concerned, there are no known dose thresholds for mesothelioma and the median latency is noted in the Royal Commission Report on Asbestos (1984) to be around 25 years. This claimant apparently meets this latency. The duration of exposure for mesothelioma is also not known since even a one-day high exposure to asbestos could trigger mesothelioma many years later. Also, cigarette smoking has been shown not to have any association in the development of mesothelioma for which asbestos is the only known causal agent confirmed by many scientific studies.  Dr. Kabir said that he had reviewed the worker s employment history and he could not have been exposed to asbestos in any of his other jobs. He suggested that the Claims Adjudicator:... focus your attention on the available evidence to convince yourself that asbestos was indeed present in the process pipe to and from the machine and there were asbestos sheets on the machine itself that the claimant operated routinely causing some potential for disturbance of the friable asbestos.  An unidentified Board staff member reviewed the materials related to the worker s asbestos exposure and wrote an undated memorandum in which she or he said that it had been confirmed that asbestos was used on the employer s premises as insulation. It was possible that the worker was exposed to some air born fibres when the asbestos was disturbed for maintenance purposes but this exposure was inconsequential and not sufficient in establishing a causal relationship.  On June 18, 1999, two employees of the Occupational Health Clinics for Ontario Workers Inc., Ms. Tew and J. Oudyk, an Occupational Hygienist, visited the worker at his home. The purpose of the visit was to evaluate the worker s occupational exposure to asbestos. In their report, they commented about the worker s exposure to asbestos while he worked as a truck driver. They said: [The worker s] work as a truck driver in the construction and demolition industries would have entailed some transportation of asbestos-containing building (ACB) materials. Particularly his work with [1 employer] ( ) would have entailed asbestos fibre inhalation exposures. Water pipes were usually made of Transite at that time. Transite is a 20% mixture of asbestos in concrete. The laying of new pipe would have entailed minimal exposure, however, the loading of old pipe and its dumping from the truck into landfill sites would have been very dusty if the material was dry. Questioning [the worker] about such exposures confirmed that they did take place and that while some loads were wet, there were some loads that were very dry and dusty. While not all his work with [this employer] would have included the re moval of old water pipes, a
12 Page: 11 Decision No. 1906/99 significant portion did. His work trucking demolition waste would likely also have included such exposure from other ACB materials found in buildings being demolished.  On July 14, 1999, Ms. Tew and Dr. Burgess reported that they had identified several possible sources of asbestos exposure for the worker. The primary source was the employer represented by Mr. Boswell in this appeal. Another possible source would have been encountered when he loaded and unloaded demolition waste for about five years when he was employed has a truck driver. Ms. Tew and Dr. Burgess concluded: (vi) [The worker] has been diagnosed with malignant mesothelioma and exposures to asbestos have been identified which may have caused this disease. The post-hearing activities (a) The further medical evidence  It will be remembered that Dr. Friedman aspirated fluid from the worker s chest on November 28, Among the materials collected after the hearing, was a report of the same date, from Dr. Ling that said that this fluid was suspicious for malignancy.  The worker had a CT scan of his thorax on April 30, This showed that the pleural densities were increasing in size.  Dr. Hollinger made follow-up reports on June 9 and August 6, In the first report, Dr. Hollinger said that the worker s illness seemed not to be progressing. In the second report, Dr. Hollinger said that he was going to do an ultrasound of the worker s chest and drain it of fluid. The drainage and a pleural biopsy took place on August 14,  A biopsy report was prepared by Dr. T. Nguyen on August 14, This showed metastatic carcinoma. No asbestos bodies were identified. Dr. Truong stated that the possibility of mesothelioma could not be excluded.  The worker had a chest tube inserted on September 16, On the same date, Dr. Hollinger said that the malignant tumor in the worker s right lung may very well be a malignant mesothelioma. On September 17, 1998, Dr. Hollinger stated that he was going to book the worker for a bronchoscopy. Dr. Hollinger inserted talc in the worker s chest on September 24,  On May 21, 1999, the worker had a CT scan of his thorax. This showed marked opacification of the right hemithorax, multiple pleural plaques, and marked pleural thickening, all in the worker s right lung. His left lung was clear.  Dr. Hollinger drained the fluid from the worker s lung on May 26, He commented that the worker had probable mesothelioma.  Dr. Hollinger reported, on November 4, 1999, that the worker had lymph adenopathy in his neck and the mass in his right lung was compressing his left chest, resulting in decreased ability to breathe.  The worker had a chest x-ray on November 5, 1999, and a CT scan on November 17, These showed that the worker s lung cancer was progressing.
13 Page: 12 Decision No. 1906/99 (b) The assessors reports 1. Dr. J.B.M. Mullen s report  Dr. Mullen is a specialist in anatomical pathology. His report was dated March 20, His report said: At your request, I have reviewed the pleural cytology and biopsy material on the above named patient forwarded from Guelph General Hospital. The material was labelled CY (two slides), CY50-98 (three slides), G (twelve slides) and G (ten slides including eight immunohistochemistry slides performed at Hamilton Health Sciences Centre). My interpretation of the material is as follows: CY : Malignant, type indeterminate CY50-98: Malignant, type indeterminate G167-98: Malignant, type indeterminate G : Malignant epithelial mesothelioma In response to your specific questions: Q. Please examine the biopsy materials and reports and advise the Panel of your diagnosis for this worker s lung condition. Can you tell if the worker has a primary neoplasm of the mesothelium of his pleura? Please explain your answer. The pleural cytology (CY , CY50-98) and first pleural biopsy (G167-98) contained isolated groups of malignant cells. The differential diagnosis included a malignant epithelial mesothelioma and a metastatic adenocarcinoma. I was unable to distinguish between the two based on this material. The second pleural biopsy (G ) contained an invasive epithelial malignant tumour. The immunohistochemical stains (calretinin, CEA, Leu M1 (CD15), and B72.3) supported the diagnosis of a malignant epithelial mesothelioma. Calretinin is a positive marker for mesothelioma that is commonly expressed in mesotheliomas but not in adenocarcinomas. CEA, Leu M1 (CD15) and B72.3 are negative markers for mesotheliomas which are commonly expressed in adenocarcinomas but not in mesotheliomas. In summary, the morphology of the pleural fluid cytology and pleural biopsies is that of a malignant epithelial tumour. The presence of positive calretinin staining with negative CEA, Leu M1 (CD15) and B72.3 staining distinguishes between a malignant epithelial mesothelioma and metastatic adenocarcinoma. I have enclosed a recent review article on the immunohistochemical diagnosis of epithelial mesothelioma for your files. Q. Is there any information that you feel would be helpful to the Panel and the parties in understanding the worker s condition and it s etiology? The worker has a malignant epithelial mesothelioma. Asbestos is the single most important causative agent of mesotheliomas. The association between asbestos exposure and mesothelioma is greater in men than in women. The threshold amount of asbestos necessary to induce mesothelioma is unknown. A dose-response relationship has been suggested; persons with a greater intensity and duration of exposure to asbestos have a higher incidence of mesothelioma. Small concentrations of asbestos have been reported to induce mesothelioma, although positive proof of low-concentration-asbestos causation of mesothelioma is lacking because mo st adults in urban populations contain asbestos in their lungs.
14 Page: 13 Decision No. 1906/99 2. Dr. J.A.M. Henderson s report  Dr. Henderson is a specialist in internal medicine. His report was dated June 15, After reviewing the documentation, Dr. Henderson answered the questions posed by the Panel members. For convenience, the Panel has set out the questions together with Dr. Henderson s responses, below: 1. Please explain for the Panel the differences between mesothelioma, malignant mesothelioma, and reactive mesothelial cells. I will define these terms and then give citations to illustrate how they have been applied or mentioned with respect to the case of [the worker]. In disease classification, the term mesothelioma describes tumours which arise in the pleura which covers the lungs, or in other serous membranes 3 such as the pericardium investing the heart, and the peritoneum lining the abdominal cavity. Mesotheliomas include a localized benign form and diffuse malignant mesothelioma. Only diffuse malignant mesothelioma is related to asbestos exposure. Historically, it is of interest that the existence of primary pleural malignancies was denied as recently as 50 years ago by some authorities, who regarded such tumours as examples of secondary pleural cancer originating in other sites, especially primary breast and lung tumours. Such a view is no longer accepted. Mesothelioma is a rare tumour in the general population, accounting for about 1% of cancer deaths, whereas secondary that is metastatic tumours of the pleura, are frequently encountered in clinical practice. Structurally the pleura is composed of a layer of connective tissue covered by a simple layer of cells known as the mesothelium. Mesothelial cells may proliferate because of irritation, for example, from an adjacent inflammatory process such as pneumonia in the underlying lung. The differentiation of such reactive mesothelial cells from mesothelioma tumour cells may be difficult and a matter for repeated scrutiny and consultation among expert pathologists. Thus, [in] the case record there is a report issued at Guelph General Hospital by the pathologist Dr E T Ling and his laboratory technologist J Samuel, concerning pleural fluid specimens aspirated from [the worker s] chest on 08 January 08, This report describes groups of abnormal mesothelial cells seen on microscopy, with the notation -? reactive? neoplastic.... A conclusive diagnosis could thus not be made on this cytologic examination, and the specimens was sent for review to Hamilton. A pleural biopsy on the same date was likewise inconclusive and similarly referred for a second opinion. From Hamilton, Dr. G. L Frank of the Henderson General Hospital agreed with the interpretation of Dr. J. Michael Kay of St Joseph s Hospital - McMaster University who reported on January 21, 1998 after examination of multiple specimens with special techniques, that he favoured a diagnosis of reactive mesothelial cells. At this stage, therefore, the pathological diagnosis favoured a benign rather than a cancerous process, although the clinical impression of [the worker s] attending physician Dr. C Gerald Hollinger in December 1997 and again in May 1998 was that of pleural malignancy. Moreover, one cytologic examination of pleural fluid had been reported as suspicious in November In such circumstances, more definitive diagnostic studies may well be called for, and in a consultation report dated January 21, 1998 from Dr. Linda LeBlanc and Dr. Malti Patel of the Hamilton Regional Cancer Centre, it was remarked that Dr. Kay had suggested open lung biopsy to further delineate the diagnosis. Dr. LeBlanc and Dr. Patel also 3 Serous membranes are so called in that they produce small quantities of serum, a clear fluid with moisturizing and lubricating properties.
15 Page: 14 Decision No. 1906/99 point out that [the worker and his spouse] felt strongly about obtaining a definitive diagnosis, and we may certainly empathize with their anxiety and their need to find out just what was the precise nature of [the worker s] illness. 2. Please review the articles provided by Mr. Herman and Mr. Boswell and comment on the reliability and validity of these articles. The article which I understand to have been provided by Mr. Herman derives from an internet site in the United States and opens, The people most at risk for developing asbestos-related diseases... are the Americans who built this nation. The article contains much useful information such as lists of trades with the likelihood of asbestos exposure and lists of asbestos-containing products, and offers guidance in obtaining the services of an experienced asbestos attorney to evaluate legal options. The article thus appears directed to prospective litigants and other interested parties. The article forwarded by Mr. Robert A Boswell as an attachment to his letter dated August 6, 1999 is a review article published in a very reputable journal by a group of university-based doctors in Belgium, one being a specialist in respiratory medicine while the other two are pathologists. The article contains much information and includes 27 literature citations of which 22 are recent ie., with publication dates in the 1990s. The article is scholarly and thorough, and contains a detailed section on the Histopathologic Diagnosis of Mesiothelioma. Under this heading the authors remark, under Differential Diagnosis: The distinction between malignant mesothelioma and reactive mesothelium or with pleural metastas is can be very difficult, especially when dealing: with very small samples or with pleural fluids... [the underlining is mine] and the authors conclude the section as follows: The diagnosis of malignant mesothelioma remains very difficult despite electron microscopic, histochemical and immunohistochemical techniques. In this review, Ramael and colleagues are providing a detailed recapitulation of existing knowledge which we can accept as well documented and valid. It is well known to clinicians and pathologists that the diagnosis of mesothelioma can be difficult and may require special techniques and skill. The complexity of the process is also detailed in a state of the art report published in Human Pathology 1999; 30: , and attached by Dr. Mullen to his letter of March 20, 2000 which is referred to under question 4 below. 3. Please explain for the Panel the significance of P53 in the diagnosis of mesothelioma. In my copy of the Case Record, p. 53 is the concluding page of the part of an Internet site publication on asbestos and litigation. As noted above, the information provided is directed to members of the public with a concern in the matter, with specific recommendations for obtaining legal aid and more general advice on seeking medical guidance. I do not feel I need comment further. 4. Please examine the biopsy materials and reports and advise the Panel of your diagnosis of this worker s lung condition. Can you tell if the worker has a primary neoplasm of the mesothelium of his pleura? Please explain your answer. I believe that it is not necessary for me to respond directly to the first part of this question, that is since the report by Dr. J Brendan M Mullen dated March 20, 2000 has reached the file. Dr. Mullen has had the opportunity to review all the pleural cytology and biopsy material forwarded from Dr. E T Ling s laboratory in Guelph, and also the special immunochemistry slides from Dr. D Daya. Dr. Daya, a Professor of Pathology at McMaster University, wrote to Dr. T Nguyen at Guelph in a report dated August 27, 1998 agreeing with Dr. Nguyen s suspicion of (malignant) mesothelioma...
16 Page: 15 Decision No. 1906/99 Dr. Daya made reference to the invasive nature of the tumour and the findings on immunochemistry. In his report of March 20, 2000 Dr. Mullen has provided a categorical diagnosis of pleural mesothelioma which thus concurs with that of Dr. Nguyen and Dr. Daya. I infer that Dr. Nguyen and Dr. Daya and hence Dr. Mullen had additional pathological tissue for study, that is following a further pleural biopsy carried out by Dr. Hollinger on August 14, 1998 when four good pleural biopsies were obtained. There is no equivocation in Dr. Mullen s report. I suggest that if there had been any uncertainty about his conclusion, Dr Mullen would likely have recommended consultation with the US-Canadian Mesothelioma Reference Panel, which is located in Vancouver. Let me add that the Chairman of the Panel is Dr. Andrew Churg who is a professor at UBC, and who has emphasized: The role of the pathologist is critical in the diagnosis of mesothelioma. The pathologist s determination must be made with great care because of the medical-legal consequences of either diagnosing or excluding mesothelioma. Churg A and Green F H Y The Pathology of Occupational Lung Disease New York: Igaku-Shoin, 1988 p. 293 Taken in conjunction with the clinical and chest x-ray features, the findings of the pathologists Dr. Daya and Dr. Mullen provide compelling evidence that [the worker] had a malignant pleural mesothelioma, and I would fully accept this diagnosis. In my opinion, it follows therefore that the view of the employer [see page 1 above] that [the worker] did not have a pleural mesothelioma, is untenable. I note that an occupational health physician and an occupational health nurse, Dr. Ken Burgess and Ms. Michelle Tew, in a concise and comprehensive case review dated July 14, 1999 state, Diagnosis does not seem to be at question but the issue of exposure is. I am in entire agreement with this report and with the concluding comments of Dr. Burgess and Ms. Tew regarding attribution. 5. Please comment on the theory that bystanders may develop mesothelioma from being around an exposed worker who has dust on their clothes or by inhaling asbestos fibres from ambient air. The article provided by Mr. Boswell, and found in Addendum #2, states... Families of asbestos workers have an approximately 1% risk... Please comment on the risk, if any, of exposure to workers who themselves may have been exposed to asbestos but who are not asbestos workers. It is well recognized that some forms of non-occupational exposure to asbestos may lead to attributable disease. Thus, household contact disease usually from the laundering of workclothes contaminated with asbestos dust has been reported, and likewise in individuals with a history of playing in mine tailings during childhood or who have lived near mines, that is, mainly from mines producing crocidolite asbestos. Asbestos-related disease has also been observed in bystanders employed in the vicin ity of a site where asbestos was being installed or removed, for example in shipyards in England, or in non-production asbestos factory workers. The risk may be small but is certainly not negligible. A painstaking and chronologic review of [the worker s] asbestos exposure history by an Occupational Hygienist John Oudyk in the Case Record concludes that he had a typical tertiary asbestos profile in keeping with what is termed bystander exposure, and I find this persuasive. 6. What is the usual latency period for the development of mesothelioma in cases of low levels of exposure? If the worker has malignant mesothelioma and if it was caused by exposure to asbestos, can you speculate about when that exposure might have taken place?
17 Page: 16 Decision No. 1906/99 The latency period from first exposure to death from mesothelioma is usually years and is rarely less than 20 years. The risk increases with cumulative exposure. With respect to the case of [the worker], I would agree with the thorough analysis of Mr. Oudyk, that occupational exposures during the 1960s and 1970s are consistent with the criteria for latency that characterize occupation-related mesothelioma. The matter of exposure and latency is also carefully considered in the report of another Occupational Hygienist Dr. H. Kabir and I concur with his remarks in this context. (c) The representatives final written submissions 1. Mr. Lovely s submissions  On June 28, 2000, Mr. Lovely advised the Tribunal that he would rely on the oral submissions made by Mr. Herman at the hearing, and on the post-hearing evidence. 2. Mr. Boswell s submissions  Mr. Boswell referred the Panel members to his oral submissions and made further submissions with respect to the reports of Drs. Mullen and Henderson.  Mr. Boswell stated that the employer s concerns are not addressed by the assessors reports and submitted that Dr. Kay s report continues to be the most reliable pathology opinion before the Panel.  Mr. Boswell noted that the worker had no direct exposure to asbestos while in the employ of the employer. He pointed out that there were flaws in Mr. Oudyk s report and that this report should be discounted with respect to its conclusions on asbestos exposure at [the employer s].  Mr. Boswell suggested that the worker might have been exposed to asbestos when he worked for the manufacturer of small asbestos lined appliances or when he worked in construction.  Mr. Boswell asked that, if the Panel members concluded that the worker suffered from mesothelioma, we direct the Board to either a lot the cost of the claim to a previous employer or apportion the cost between employers. (vi) The law and Board policy  On January 1, 1998, the Workplace Safety and Insurance Act (WSI Act) took effect. This legislation amends portions of the Workers Compensation Act, which continues to apply to injuries which occurred before January 1, Section 145 of the Workers Compensation Act provides that the pre-1985 Act continues to apply to workers who are injured prior to April 1,  The worker takes the position that his mesothelioma resulted from exposure to asbestos in the workplace before April 1, 1985, and that the pre-1985 Act applies in this case. Tribunal jurisprudence has held that the accident date is when the condition becomes symptomatic and is diagnosed, as this is when the worker generally becomes impaired. Section 134 of the pre-1997 Workers Compensation Act states that benefits are payable where the worker suffers from an occupational disease and is thereby impaired. It further states that the impairment is the happening of the accident (cf Decision No. 640/96). Since the worker became symptomatic and stopped working in late 1997, the pre-1997 Workers Compensation Act applies in this appeal.
18 Page: 17 Decision No. 1906/99  Mesothelioma was entered into Schedule IV of the Workplace Safety and Insurance Act, effective May 28, The effect of this change is that if a worker has been diagnosed with mesothelioma and she or he worked in one of the processes listed in column 2 of the regulation, the disease is presumed to be work-related and the worker will receive compensation benefits. Column 2 lists the following: any mining, milling, manufacturing, assembly in construction, repair, alteration, maintenance or demolition process involving the generation of air borne asbestos fibres.  A change that is relevant to this appeal is that the Appeals Tribunal is now required to apply Board policy in accordance with sections 112 and 126 of the WSI Act. Prior to this, the Tribunal did consider and apply Board policy in deciding appeals, although the prior Act did not contain this express provision.  As is required by section 126(2) of the Workplace Safety and Insurance Act, 1997, the Board advised the Tribunal of the policies that are applicable in this appeal. (vii) Conclusions (a) The worker s appeal  The worker is seeking recognition that his mesothelioma resulted from exposure to asbestos in the workplace, and all the benefits that would flow from such a decision.  For the reasons that are set out in (b) below, the Panel finds that the worker was suffering from mesothelioma and we accept that his death resulted from this condition. The Appeals Resolution Officer also accepted that the worker had mesothelioma but denied him benefits because he was unable to establish that the worker had sufficient exposure to asbestos in the workplace to have caused this disease.  The Panel accepts Dr. Kabir s statements that asbestos exposure is the only known causal agent in the development of mesothelioma and that there is no known dose threshold between exposure to asbestos and the development of mesothelioma.  The Panel members note that an unidentified member of the Board staff confirmed that asbestos was used as insulation and that it was possible that the worker was exposed to some fibres. That staff member felt that the exposure was inconsequential. Given Dr. Kabir s statement that mesothelioma can develop from any exposure to asbestos, we do not share the opinion of that staff member that the worker s exposure was inconsequential.  According to Dr. Kabir, the median latency period set out in the Royal Commission Report on Asbestos (1984) was about 25 years. Dr. Henderson said that the latency period was usually between 30 and 40 years and rarely less than 20 years.  The worker appears to have been employed in at least three occupations where he could have been exposed to asbestos. The first was when he was employed by the accident employer in this appeal. The evidence reviewed earlier indicates that asbestos was present in various locations at this employer. From the Panel s calculation, the worker was employed for a total of three years between August 1966 and November 1969 and six months between November 1973 and May From first employment in August 1966 until he first exhibited symptoms in
19 Page: 18 Decision No. 1906/99 mid-1997, was 31 years. From last employment in May 1974 until he became symptomatic was 23 years. The Panel members find that the worker s employment with the employer was consistent with the latency period set out in the Royal Commission Report and with that suggested by Dr. Henderson.  The second employment where the worker could have been exposed to asbestos was between 1969 and 1971 when he assembled air conditioners. He testified that this company assembled small appliances and that asbestos was used as the insulation. Although he did not assemble these products, he walked through the areas where they were being assembled 20 or 30 times a day. This exposure was between 26 and 28 years before he became symptomatic. Accordingly, this exposure is also within the suggested latency periods.  The worker s third possible exposure occurred when he was working as a heavy equipment operator. The Panel members note that Ms. Tew and Dr. Burgess felt that exposure to asbestos was possible when he loaded old pipe, transported materials from demolished construction, and dumped the materials in landfill sites. This exposure was from 1972 to 1977, or between 20 and 25 years before the worker became symptomatic, and is also within the latency period.  There is no evidence of any non-workplace exposure to asbestos. The medical evidence indicates that this is a rare type of cancer and asbestos is the single most important causative agent. There is no known safe level of exposure and small amounts of asbestos have been reported to induce mesothelioma. The worker s employment with each of the three above listed employers was consistent with the latency requirements for the development of mesothelioma.  The pre-1997 Act states: 4(3) Where the accident arose out of the employment, unless the contrary is shown, it shall be presumed that it occurred in the course of the employment and, where the accident occurred in the course of the employment unless the contrary is shown, it shall be presumed that it arose out of the employment.  From the evidence before us, the Panel members find that it is equally as likely that the exposure to asbestos that lead to the development of the worker s mesothelioma could have occurred at each of the three employers. The Board is to apportion equally among the employers. (b) The employer s cross-appeal  The employer submitted that the medical evidence did not support the diagnosis of mesothelioma and cross-appealed this portion of the Appeals Resolution Officer s decision. The employer relied on Dr. Kay s report of January 21, 1998, in which Dr. Kay opined that the worker had reactive mesothelial cells rather than mesothelioma.  The Panel members are persuaded by the reports of Drs. Mullen and Henderson that the worker had malignant epithelial mesothelioma. We accept Dr. Henderson s explanation with respect to the reason that Dr. Kay and Dr. Frank believed the worker had reactive mesothelial cells; specifically, that the pathology in 1998 seemed to indicate that the worker s condition was a benign rather than a malignant one. Given that Dr. Mullen had access to all the clinical reports, chest x-rays, and the slides taken at biopsies, the Panel members find Dr. Mullen s report to be definitive.
20 Page: 19 Decision No. 1906/99  We note that Dr. Hollinger diagnosed malignant mesothelioma; Dr. Nguyen was unable to rule out malignant mesothelioma in the worker; and Dr. Daya confirmed the diagnosis of malignant mesothelioma. Accordingly, the preponderance of the medical evidence apart from the assessors opinions, supports this diagnosis. THE DECISION  The worker s appeal is allowed.  The employer s cross-appeal with respect to the diagnosis of malignant melanoma is denied.  Because the worker was employed in three different industries during the latency period, it seems equally likely that each of the exposures could have led to his mesothelioma. The Board is to apportion costs among the three classifications equally. DATED: February 14, 2001 SIGNED: S.J. Sutherland, C.J. Robb, D.B. Beattie