WORKPLACE SAFETY AND INSURANCE BOARD
APPEALS RESOLUTION OFFICER DECISION
DECISION NUMBER: 20100070
OBJECTION BY: Estate of Worker
PARTICIPANTS: Worker’s Estate, Estate’s Representative, Employer, Employer’s Representative
HEARING LOCATION: N/A
ISSUE
The estate claimed entitlement for kidney cancer as causally related to the workplace exposures between 1973 and 1999.
HOW THE ISSUE ARISES
The worker passed away on August 2, 1988 due to the spread of his originally diagnosed kidney cancer.
The claim was submitted to the Workplace Safety and Insurance Board (WSIB) on behalf of the widow by the local union as part of a cluster of cases.
In order to adjudicate the claim, the WSIB requested the outstanding relevant medical reports. The WSIB also obtained exposure information and the claim was reviewed by the WSIB’s occupational hygienist, medical consultants and the issue of kidney cancer and steelworkers was reviewed by the WSIB’s medical occupational disease policy branch. In addition, the medical occupational policy branch also reviewed the issue of kidney cancer and exposure to trichloroethylene (TCE).
Following review of the exposure, as well as the medical and scientific evidence, it was concluded that the evidence did not support a causal relationship between the worker’s exposures in the workplace and the development of his kidney cancer. Specifically, the WSIB considered his exposure to asbestos and TCE.
The union representative objected to the denial of entitlement and written submissions were made.
AUTHORITY
Operational Policy Manual (OPM) document(s):
- 11-01-01 – Adjudicative Process
- 11-01-02 – Decision-Making
RESOLUTION METHOD AND PROCESS
This decision is made with the information contained in the record.
ASSESSMENT OF THE EVIDENCE AND SUBMISSIONS
Employment History
The employer has provided the following work history in their letter of February 12, 2007:
October 1960 to March 1973 the worker was an Electrical Repairman Apprentice in the Maintenance Department.
March 1973 to August 1973 he worked in Electrical Repair “C” in the Maintenance Department.
August 1973 to February 1980 he worked in Electrical Repair “A” in the Maintenance Department.
February 1980 to February 1980 he worked in Instrument Repair “C” Utilities Department.
February 1980 to March 1998 he worked in Instrument Repair “A” in the Maintenance Department.
March 1998 to February 1998 he worked as Electrical Maintenance Technician in the Electrical Maintenance General Department.
The employer noted in their letter of February 5, 2007 as follows:
“Electrical Repairman worked in various departments maintaining electrical supply and trouble shooting, and repairing electrical equipment. Occupational exposures include the potential for exposure to asbestos from electrical motor components, switch insulating materials and wire insulating compounds.” It was noted that the worker was exposed to potential contaminants; total suspended particulate, solvents, calcium oxide, iron oxide, sulphur dioxide gas, oils and greases and asbestos.”
The worker was diagnosed with kidney cancer. The pathology report of November 25, 1987 noted that following a left radical nephrectomy, the microscopic examination showed a large renal adenocarcinoma.
The worker’s possible employment exposures included asbestos and TCE.
Asbestos Exposure and Renal Cancer
The claim was reviewed by the WSIB’s occupational hygienist who provided the following opinion in memo 12 with respect to asbestos:
“Based on a review of the available literature (since there are no asbestos exposure available in our database specifically for electricians but there are three values for brake repairman, possibly not appropriate for electricians), it appears that electricians did have the potential for exposure to asbestos. However, the literature referenced below and summarized as above, the levels could be at or just above the current asbestos exposure limit of 0.1 fibres/cc”.
The WSIB’s hygienist went on to state: “The employer and the literature report cited a maximum of 5 per cent of electrician’s time in contact with asbestos containing materials. This claimant worked 31 years with Algoma Steel and 5 per cent of his exposure time could be about 1.6 years in which he could have come in contact with asbestos in his line of work on a repeated daily basis.”
The WSIB’s Medical And Occupational Disease Policy Branch had conducted a review titled: “Asbestos Exposure and Renal (Kidney) Cancer” in which it was concluded that there is limited evidence of an excess risk of renal cancer for occupations with high cumulative levels of asbestos exposure (e.g. asbestos production workers and insulators) and with considerable exposure, for example, employment greater than 20 years.
In support of the claim, Dr. A. R. of OHCOW provided references from studies that support a relationship between the development of renal cancer and asbestos exposure.
In reviewing the opinion of Dr. A. R. and the ODPR review, it is accepted that the studies that support a relationship between renal cancer and asbestos exposure show that this is most likely in cases with high cumulative levels of asbestos exposure and of considerable intensity and duration. As noted by the WSIB’s literature review, this is with employment greater than 20 years of considerable exposure.
In the case of this worker, in his job as an Electrician, while it is likely that he did have asbestos exposure, the intensity and duration of the exposure would not meet that observed in the studies cited by Dr. A. R. and in the ODPR review.
The available evidence therefore does not support a causal relationship to development of the worker’s renal cancer and his asbestos exposures. In coming to this conclusion, I also note that there was no evidence of any asbestos related dust effects (pleural plaques, asbestosis or COPD) that would indicate that he had high levels of asbestos exposure.
The available evidence therefore does not support a causal relationship between the development of the worker’s renal cancer and his asbestos exposure.
TCE Exposure
The evidence in the form of the information obtained from co-workers indicate that the TCE exposure occurred with the use of the lubricant Chroma Tap. As noted by the WSIB’s occupational hygienist in memo 16, research did not support exposure and uptake levels. The opinion was expressed that the potential for some exposure to TCE may have existed on an intermittent daily basis for a short-term (a few minutes at a time). It was therefore not accepted that there was long-term and a high duration of exposures.
The medical support for a causal relationship between TCE and the development of renal cancer is provided by way of the opinion of Dr. A. R. who cited studies to support this opinion.
The case was reviewed by the WSIB medical consultant, who provided the opinion dated April 24, 2007 that from a literature review, there is no convincing epidemiological evidence of a relation between renal cancer and employment in the steel industry in general. With respect to TCE, he opined, that the recent evidence to date does not support an occupational cause for the worker’s renal cell carcinoma.
The ODPR reviewed the issue of renal cancer and steelworkers in the review titled: “Steelworker Risks for Lung, Kidney and Bladder Cancer.” In that review, it was found that there is inconclusive evidence for increased risks of kidney cancer in coke oven workers. For iron and steel foundry and iron and steel industry workers, the review of cohort studies was suggestive of an increased risk. Surveillance studies and case control studies were in agreement with findings in the cohort studies. Based on these the evidence of kidney cancer in iron and steel foundry and iron and steel industry workers would be considered limited.”
The WSIB ODPR conducted a more comprehensive review in March 2009. This review is titled: “Assessment of Kidney Cancer Risk in Steelworkers, Including Foundry and Coke Oven Subgroups (March 2009).” This study reported that cohort studies of bladder plus kidney cancer risk in steelworkers largely showed no elevated risks. Ten surveillance studies had reported inconsistent results with the smallest studies showing non-significantly elevated risks and the larger study showing non-significant slightly decreased risks. The study went on to state that the addition of all unique results for foundry and coke oven workers did not substantially alter the finding for kidney cancer in steelworkers. Overall, significantly elevated risks were observed in case control studies, based primarily on one multicenter study. All surveillance studies and cohort studies for foundry and coke workers did not show an overall significantly elevated risk. All studies combined showed an overall SRE that was not significant, but was heterogeneous. Although there is some suggestive evidence of an increased risk of kidney cancer from the case control studies, the overall picture of inconsistent findings, weak study designs, and lack of evidence for a dose response trend indicate that the evidence for kidney cancer risk in the steel industry is inconclusive.
In looking at the most recent IARC monograph, Volume 63 for TCE, I note the following is stated with respect to kidney cancer on page 134:
“The occurrence of cancer of the kidney was not elevated in the cohort studies; however, a study of German workers exposed to trichloroethylene revealed five cases of renal cancer whereas no case was found in an unexposed comparison group. The study may, however, have been initiated after the observation of a cluster. A case control study and the multisite cancer study, both from Montreal, Canada, provided discordant results with regard to cancer of the kidney...”
The following is stated on page 136 IARC monograph, Volume 63:
“Acute toxicity of trichloroethylene in rodents and humans is low. After high doses of trichloroethylene are administered repeatedly to rodents, damage is seen in liver and kidney (in mice and rats) and in lung (in mice only). Repeated exposure of humans in the workplace appears to have no marked toxic effects on the kidney or liver....”
The overall evaluation in point two on page 137 states as follows:
“Several epidemiological studies showed elevated risks for cancer of the liver and biliary tract and for non-Hodgkin’s lymphoma.”
The conclusion of IARC is that repeated exposure of humans in the workplace appears to have no marked toxic effects on the kidney or liver when it comes to trichloroethylene exposure.
Overall, the weight of the evidence does not support a causal relationship between the worker’s exposure to trichloroethylene in the Chroma Tap and the development of his renal cancer.
CONCLUSION
I conclude the available evidence does not support a causal relationship between the worker’s exposure to asbestos and trichloroethylene and the development of his renal cancer. The available evidence does not support a causal relationship between the development of his renal cancer and his employment and general exposures in the workplace.
The objection of the Estate is therefore denied.
Dated: April 19, 2010
N. Kissoore
Appeals Resolution Officer
Appeals Branch