WORKPLACE SAFETY AND INSURANCE BOARD
APPEALS RESOLUTION OFFICER DECISION
DECISION NUMBER: 20110035
OBJECTION BY: Employer
PARTICIPANTS: Employer, Employer Representative, Worker, Worker Representative, Witnesses
HEARING DATE November 15, 2011
ISSUE
The employer objects to the allowance of this claim for Idiopathic Parkinson’s Disease.
HOW THE ISSUE ARISES
The worker submitted a claim to the WSIB for his condition diagnosed as Idiopathic Parkinson’s Disease in 2008.
The WSIB obtained the necessary medical and exposure information and adjudicated the claim.
It was determined that the worker had been employed as follows:
Before 1976 with an electrical contractor as a general labourer.
From 1976 to 2008 with the employer. From 1976 to 1980 he worked as an operator assistant working on the end of the production line, monitoring and packing the end products of NBR.
From 1980 to 1983 he worked as an operations assistant in the Utility/Steam Production Department, maintaining the boilers in the power house.
From 1983 to 2008 he worked as a mechanic/millwright installing, maintaining, cleaning, repairing equipment, in the Maintenance Shop.
It was determined that based on an occupational hygiene assessment that the worker had exposure to N-Hexane of a moderate degree for some 20 years. He was also likely exposed to welding fumes containing Manganese of a low to moderate nature.
Considering his exposure to manganese and hexane, the decision maker accepted that the exposure which was classified at “moderate levels” for 20 years could have contributed to the development of his Parkinson’s Disease. The claim was therefore allowed.
The employer has objected and evidence obtained at the hearing.
AUTHORITY REFERENCE
Workplace Safety and Insurance Act (the Act) Section 2(1) and Section 15.
ASSESSMENT OF THE EVIDENCE
Based on the assessment of the worker’s exposures by the WSIB’s occupational hygienist, the agents of interest are Acrylonitrile, N‑Hexane and welding fumes (containing Manganese).
I will deal with the evidence obtained at the hearing with respect to these three exposures.
TESTIMONY OF J. M.
Mr. M. testified he has been the Health and Safety Supervisor with the employer for the last three years. Prior to that, he was a Production Supervisor in the Butyl Unit for some two and one‑half years, a Shift Supervisor in the Olefins Unit for approximately two and one‑half years and prior to that he was a Human Resource Specialist for 11½ years. He also worked as a Rehabilitation Counsellor for the WSIB for some two and one‑half years before joining the employer.
Mr. M. notes that he is involved in the day to day health and safety issues onsite and oversees a staff of three. He is involved in health and safety training as well as maintaining all necessary health and safety plans. He oversees occupational health and safety sampling and distribution of results.
With respect to the employment in the Olefins Unit, the process uses Isobutylene string to extract Butadiene. The Butadiene is then fed into an extraction unit to remove and make isobutylene which is used to make synthetic rubber. He described the finished product as looking like popcorn which is then shipped to manufacturers. He noted that all of the processes are self‑contained within equipment. There is therefore no exposure to fumes.
The Olefins operator oversees the process by computer control with an operating technician at the end of the line who manually handles bales of rubber.
In the Butyl operations, he testified that the process is similar to that in the Olefins except that the finished rubber is removed by a forklift instead of manually.
Maintenance mechanics troubleshoot and fix equipment.
Any welding is done in a specific welding shop where they do major projects. They also ship welding jobs to subcontractors offsite. He testified that the Maintenance Shop does have one welder assigned to each maintenance group. This welder would do smaller welding shops using a snorkel ventilation at the workstation. He noted that this area is typically 40 feet away from Mr. Welsh’s location.
He testified that the worker worked between 1976 and 1980 on the NBR Unit as it processed equipment where he worked at the end of the line removing the finished product. The area was monitored regularly for Acrylonitrile and Butadiene with all levels below the accepted limits.
Between 1988 to 1993 the worker worked in the utilities area at the Power Plant where steam generation is used to produce electricity. The worker would not have had any exposure to any fumes or chemicals.
He noted that the worker also worked as a Maintenance Mechanic in the Olefins Unit but would not have likely had any significant exposure to any fumes. He explained that any equipment were removed by operating technicians. The process was to shut off the power, steam out the lines, rinse the lines with steam, nitrogen and air. The maintenance mechanic would then come in and remove the equipment for maintenance and service. He stated that any exposures would be residual fumes from Butadiene, Isobutalene and Acrylonitrile. There was no exposure to N‑Hexane or Acrylonitrile as they were not used in this Olefin process. The majority of the worker’s work time as a mechanic was in the Olefins Unit.
With respect to N-Hexane exposure, he noted that this would occur in the Butyl Unit and any exposure would have been occasional whenever servicing equipment. He noted there was never any spray containing N‑Hexane. He testified that the air monitoring results provides for a limit of 50 parts per million (PPM). The highest reading taken was 0.90 PPM. This would have occurred in the Butyl 1 and 2 Units.
With respect to welding fumes, Mr. M. testified that the worker would not have had to do any actual welding as this job was a separate classification. He noted that personal protective equipment are provided such as respirators and are used regularly and appropriately. He testified that whenever a job is assigned, a work order (permit) is issued by the Operations Area outlining the job and includes the tasks to be performed, and also whether personal protective equipment is required.
TESTIMONY OF DR S.
Dr. S. testified that he is an Occupational Medicine Consultant with expertise in occupational hygiene and toxicology. He has reviewed all of the medical and exposure information in the claim file.
Acrylonitrile
With respect to Acrylonitrile, he noted that this is a designated substance however; he noted that he was only able to find a single Chinese study on the issue of Parkinson’s Disease and Acrylonitrile. The study is not available as it was done in China. He noted that the study dealt with Acrylonitrile poisoning and the development of Parkinson’s. Since the worker has never had Acrylonitrile poisoning, he concluded that the available literature does not support a relationship between exposure to Acrylonitrile and Parkinson’s Disease.
N-Hexane
With respect to the worker’s N-Hexane exposure, he testified that N-Hexane is a commonly occurring substance as it constitutes 1 per cent of gasoline. He stated that in looking at the case, one must look at the dose. He noted that it is a common principle of toxicology that “the dose makes the difference.” He explained that the American Conference of Industrial Hygienists (ACGIH) came up with the concept of Threshold Level values which are used in Ontario. As the dose makes the difference, he stated that working below the TLV of a designated substance causes no effect. The TLV is used to determine the dose.
N-Hexane is a volatile substance which is produced naturally within the human body. He conducted a literature search and could find three articles which supported a relationship between N‑Hexane exposure and Parkinsonism. The relationship occurred with high and prolonged exposure to N‑Hexane.
Dr. S. explained that Parkinsonism is different from Parkinson’s Disease. In Parkinson’s Disease, the brain of the individual affected is unable to produce Dopamine. The use of the drug L Dopa therefore shows improvement. Mr. Welsh has been diagnosed with Idiopathic Parkinson’s Disease and has responded to treatment with L Dopa.
Dr. S. explained that Parkinsonism occurs when the pathway which uses Dopamine is disrupted as seen in a toxic effect. In the cases of Parkinsonism, the use of L Dopa is ineffective.
Dr. S. therefore concluded that since the worker suffers with Parkinson’s Disease and not Parkinsonism, any N‑Hexane exposure cannot be seen as a cause.
Welding Fumes
With respect to the exposure to Manganese from welding fumes, Dr. S. testified that Manganese is used in the welding rods. The effects of chronic Manganese exposure is noted in the Globus Pallidus of the brain and not in the Substantia Nigra as seen in Parkinson’s Disease. The effect of high welding fumes (with manganese) is manganism, which results in a uniique gait, the “cock walk”.
Dr. S. noted that the occupational hygiene report on file used the exposure of mechanics using a spray as a comparable which should not have been done. He noted that the hygienist concluded that the exposure was moderate but in his opinion stated that the exposure for the worker was low.
Dr. S. noted that the worker was not a welder by profession and even though he may have been in the same building at times when welding was being done, this does not equate to the same exposures. He agreed with the WSIB’s occupational hygienist that the welding fumes exposure was low.
With respect to the balance of the occupational hygiene report on file, he noted that the hygienist concluded that the worker had secondary Parkinsonism however; this is not a diagnosis that he was able to confirm from the file.
ASSESSMENT OF EVIDENCE
The testimony of Dr. S. is compelling and consistent with the information on file and what is generally known about Parkinson’s Disease, Parkinsonism and Manganism.
The WSIB did not allow this claim as related to exposure to Acrylonitrile and as noted by Dr. S., he was unable to find any evidence in the literature of a known relationship between Parkinson’s Disease and Acrylonitrile.
With respect to N-Hexane, the evidence is that the worker would have been exposed to this agent at levels below the TLV. In addition, the scientific and medical literature supports a relationship between N-Hexane exposure and Parkinsonism however; the worker suffers with Parkinson’s Disease not Parkinsonism. The weight of the evidence therefore does not support that the worker’s exposure to N‑Hexane was contributory to the development of his Parkinson’s Disease.
With respect to his Manganese exposure from welding, the evidence of Dr. S. and from the WSIB’s occupational hygiene assessment is that his exposure was low. In addition, the worker does not have the typical signs of Manganism which, as specified by Dr. S. includes signs and symptoms similar to those of Parkinson’s Disease however, there is a distinguishing “cock walk” which was never found with the worker. The diagnosis of the worker’s condition is that of Parkinson’s Disease and not Manganism. Therefore, the evidence does not support that the worker’s low exposure to Manganese from welding fumes was contributory to the development of his Parkinson’s Disease.
CONCLUSION
The available evidence does not support a causal relationship between the development of this worker’s Idiopathic Parkinson’s Disease and his workplace exposures. The allowance of the claim is therefore overturned.
As the decision to allow and pay benefits in this claim was made in good faith by the WSIB, any overpayment is non‑recoverable and must be removed from the employer’s Cost Statement. If necessary, an adjustment from the employer’s New Experimental Experience Rating (NEER) statement is in order.
The employer’s objection is granted.
DATED December 30, 2011
N. Kissoore
Appeals Resolution Officer
Appeals Branch