The Appeal CommissionThe Workers Compensation Act of Manitoba

The crux of this appeal deals with the date on which the asbestos exposure caused a loss of earning capacity.

Background

The worker has a past history of lung conditions prior to 2004. In the 1950s, the worker had a spot on his right upper lung that was initially thought to be tuberculosis though it was never diagnostically confirmed. Then, in the 1960s he had a lobectomy to this same area. The reasons for this lobectomy have never been elicited. The worker has also been diagnosed with several other medical conditions and in particular, chronic obstructive pulmonary disease (“COPD”) and rhinitis. He is also a former light smoker.

The worker began working for the accident employer in the 1960s. It is not disputed that his duties entailed working with asbestos materials.

Medical Evidence

The worker’s lung condition has been diagnosed as asbestos related pleural disease which is displayed by pleural thickening and eventually pleural plaques. Pleural thickening and plaques have been detected on x-ray and CT scan:

• September 24, 1982: Right apical pleural thickening with pulmonary scarring in the right upper lobe was seen with associated loss of lung volume. Left lung and pleura were normal.
• August 2, 1988: No change since August 1984. Right apical pulmonary and pleural scarring with associated loss of volume in the right upper lobe was noted as was pleural scarring at the right costophrenic angle. Left lung and pleura continued to be normal.
• July 15, 1992 showed hyperinflation of the lungs due to COPD with old right apical pleural thickening and linear scarring in the right upper lobe. Minor tenting of the right hemidiaphragm was also seen with old right basal pleural thickening. There was also a small amount of pleural thickening along the left lateral chest wall which was unchanged from January 1992.
• November 1, 1994 showed pleural thickening in the right apex and tenting of the right hemidiaphragm. The findings were unchanged from January 1993;
• June 5, 2003: The lungs appeared hyperinflated in keeping with COPD. There was also slight linear pulmonary scarring in the right upper lobe, left lung was clear. There was also chronic right apical pleural thickening.
• October 16, 2003: There was a faint increased density in the lateral left mid to lower lung peripherally which could suggest pleural calcification. There was marked apical pleural thickening in the right lung.
• May 27, 2004: Some small non-calcified pleural plaques were seen at the left lower lobe posteriorly and posterolaterally. A few calcified pleural plaques were seen at the left upper lobe anterolaterally and there were some apical pleural thickening at the right apex. Minimal fibrotic change was also seen at the right lower lobe anteriorly and lateral segment of the right middle lobe. There was some focal scarring at both upper lobes posteriorly. Minor scarring was seen adjacent to the right hemidiaphragm laterally and anteriorly. A small focal pleural calcification was also demonstrated in the right upper lobe laterally. The pleural thickening and calcification was suggestive of very mild asbestos related pleural disease. There was also minor fibrotic change at the right base and apical regions.
• July 10, 2004: There is considerable right apical pleural thickening and there are some pleural plaques at the left lower lobe and there is pleural thickening at the right costophrenic angle, all unchanged from the 17^th of August 2003. On previous examinations this has been called asbestos-related pleural disease and this remains stable.

Two issues arose with respect to the pleural thickening and plaques – what was related to the asbestos exposure and did it cause a loss of earning capacity such that it would entitle the worker to wage loss benefits.

These issues were explored by an internal medicine consultant to the WCB. Though several of his reports are on file, there is only one which really deals with these issues squarely - a report of March 9, 2006.

The WCB medical consultant noted that the x-rays showed evidence of the prior lobectomy as well as two small areas of pleural thickening on the left side. The CT scan confirmed this but also showed some linear fibrotic scarring on the right side. It was his opinion that the changes to the right side of the lung were all due to the prior lobectomy (35% of the worker’s lung function) and not the asbestos exposure. On the contrary, the changes on the left lung, first noted in January 1992, were related to the asbestos exposure. He did not think that the left lung changes would have caused the worker any impairment at that time. He pointed out that “there is a long lag time between exposure and development of pleural plaque”.

With respect to the impact of the pleural thickening and plaques on the worker’s left lung, pulmonary function tests done on the worker on August 18, 2005 only revealed minor airflow limitation. The impairment rating related to asbestos related pleural plaques at that time was as follows:

“…The uncorrected impairment rating is 8.46%. This, however, required correction for air flow limitation which is not related to pleural plaque. It also requires correction for chronic rhinitis which would give symptoms of cough and sputum production. The final correction is for surgery on the right lung where a part of the right lung was removed. This would tend to reduce the total lung capacity and diffusion capacity. The corrected rating therefore is 1.5%.”

The consultant added that a stress test done in June 2001 revealed that the worker would have been capable at that time of sawing wood, heavy shovelling, digging ditches, tending furnaces, jogging at 5 miles per hour, swimming or rowing. Therefore, before 2001 there was “no limitation to his physical activity”.

The worker’s family physician wrote an August 31, 2006 letter which appears to suggest that all of the worker’s breathing problems are related to the asbestos exposure. This letter must be contrasted to a June 9, 2004 letter of referral that clearly states that the worker suffered from both asbestos related disease and COPD. A respiratory specialist to whom the worker was referred wrote on May 31, 2004 that the pleural plaques due to asbestos did not require specific treatment. On the other hand, the worker’s moderate COPD did require treatment for respiratory problems which included shortness of breath. Another doctor downplayed the impact of the asbestos related disease on the worker’s condition as compared to the COPD. On July 19, 2004 he wrote: “There is no doubt that he will complain to you about the fact that this is all related to asbestos and asbestos related lung disease. He has no evidence of asbestosis, only evidence of benign asbestos related pleural disease – fortunately.”

Analysis

To accept the worker’s appeal we must find that he experienced a loss of earning capacity as a result of his work-related injury as of September 1, 1988. We are unable to make that finding.

The pulmonary function tests performed in 2001 and 2005 overwhelmingly suggest that the worker would have been able to carry out his regular duties with his employer in September 1988. On the basis of this evidence, we find it more likely than not that the worker did not have any medical restrictions related to his compensable asbestos exposure that would have led to a loss of earning capacity effective September 1, 1988.

For these reasons, we find that the worker is not entitled to wage loss benefits effective September 1, 1988.