No. 91-442 

IN THE SUPREME COURT OF THE STATE OF MONTANA 

1992 

IENRY E. NELSON, 

Claimant and Appellant, 

-vsSEMITOOL, INC., and EBI ORION GROUP, 

Defendants and Respondents. 

APPEAL PROM: District Court of the Workersf Compensation Court, 

The Honorable Timothy W. Reardon, Judge presiding. 

COUNSEL OF RECORD: 

For Appellant: 

Kenneth E. O'Brien, Hash, O'Brien & Bartlett, 

Kalispell, Montana. 

For Respondent: 

Robert E. Sheridan, Garlington, Lohn 6 Robinson, 

Missoula, Montana. 

Submitted on ~riefs: February 13, 1992 

Filed: 
Justice R. C. McDonough delivered the Opinion of the Court. 

Henry E. Nelson (Nelson) appeals from an order of the Workerse 

Compensation Court attributing fifty percent of his disability to 

an occupational disease resulting from his employment with the 

respondent, Semitool Inc., and fifty percent to a preexisting 

disability. Nelson asserts that the occupational disease from 

which he suffers is fully compensable by Semitool and was 

inappropriately apportioned by the Department of Labor. We affirm. 

The single issue for our review is whether the Workerse 

Compensation Court erred by apportioning fifty percent of Nelson's 

current disability to a preexisting disability. 

From 1964 until 1969, Nelson was an employee of the United 

States Postal Service. While employed by the postal service Nelson 

injured his back necessitating a lumbar spinal fusion. His back 

condition prevented him from performing his postal service duties 

and he began receiving federal workers' compensation benefits. 

Nelson received full disability benefits until 1978 and appears to 

continue to receive partial benefits at present. 

From 1978 until 1982, with the exception of approximately 

seven months, Nelson worked as a hardware store clerk. There is 

conflicting evidence regarding what, if any, back problems Nelson 

experienced while employed as a clerk. There is evidence that 

Nelson consulted with a local orthopedist and reported low back 

pain that radiated into his legs during this period. 

In 1982, Nelson began working for Semitool, Inc. Because of 
his prior back condition, Semitool required a physical. Nelson was 

cleared to lift 100 pounds on a regular basis. From 1982 until 

1988 Nelson held several jobs with Semitool, each of which 

resented severe physical demands including heavy lifting. In 

1988, Nelson began experiencing back problems which grew 

progressively worse culminating in Nelson's inability to continue 

work, 

The Department of Labor directed that Nelson be examined by a 

member of the Occupational Disease Panel to determine if he 

suffered from an occupational disease. Nelson was examined by Dr. 

W,J. McRinstry who concluded that Nelson's back problems were 

related to his employment at Semitool. A second examination was 

conducted by Dr. PlcDonald who concluded that Nelson's back pain was 

not attributable to his work at Semitool but to his prior injury 

and the lumbar fusion. Because of the differing opinions, a third 

doctor, Dr. Jacobson, was appointed to review the case and act as 

referee. Dr. Jacobson concurred with Dr. McDonald and on this 

basis the Department of Labor denied Nelson benefits under the 

Occupational Disease Act. 

Nelson appealed the Department of Labor decision and a hearing 

examiner was appointed. The hearing examiner determined that 

Nelson did suffer from an occupational disease as a result of the 

work at Semitool but that under 539-72-706, MCA, Semitool was (only 

fifty percent responsible for the current condition. Both parties 

to the Workers' Compensation Court and the hearing 
examiner's conclusion was affirmed. 

In addition to the reports and depositions of the above 

mentioned examining doctors, the record includes the opinions of 

Nelson's treating physicians, Drs. Ingham and Stephens. All of the 

doctors appear to agree that Nelson is suffering from a condition 

called spinal stenosis. Spinal stenosis is the narrowing of the 

area through which the nerves pass in the spinal column. The 

stenosis in Nelson's case is a result of increased bony growth or 

hypertrophic bone growth that has developed at the site of the 1968 

bone fusion. There is conflicting evidence regarding whether or 

nat the work at Semitool caused, accelerated, aggravated or is 

totally unrelated to Nelson's condition. 

Nelson argues that at the time he went to work for Semitool he 

was completely recovered from his prior injury and that his current 

condition is the result of his work at Semitool. Therefore, Nelson 

contends Semitool is liable for one hundred percent of his current 

occupational disease. There is no dispute that Nelson is disabled 

at least part of the disability is an occupational disease 

resulting from his work for Semitool. The current dispute 

requiring our resolution is whether, under § 39-72-706, NCA, 

Nelson's disability is appropriate for apportionment between his 

preexisting condition and the occupational disease. 

Section 39-72-706, MCA, provides in pertinent part: 

Aggravation. (1) If an occupational disease is aggravated 

by any other disease or infirmity not itself compensable 

or if disability or death from any other cause not itself 

compensable is aggravated, prolonged, accelerated, or in 
any way contributed to by an occupational disease, the 

compensation payable under this chapter must be reduced 

and limited to such proportion only of the compensation 

that would be payable if the occupational disease were 

the sole cause of the disability or death as such 

occupational disease as a causative factor bears to all 

the causes of such disability or death. 

The Workers"ompensation Court concluded that employment with 

Semitool accelerated Nelson's disease to the extent that Nelson 

could no longer perform his job. Semitool was held liable for the 

portion of the disability determined to be aggravated and 

accelerated by Nelson" employment with them. The remaining 

Xiability was affixed to Nelson's preexisting condition. 

It is not the function of this Court to reweigh the evidence. 

We will uphold the findings and conclusions of the Workers1 

Compensation Court if they are supported by substantial credible 

evidence in the record. Eastman v. Atlantic Richfield Co. (19891, 

237 Mont. 332, 777 P.2d 862. Where the findings are based on 

conflicting evidence, the Court's function is to determine whether 

there is substantial evidence to support the findings and not to 

determine whether there is sufficient evidence to support contrary 

findings. Little v. Structural Systems (19801, 188 Mont. 482, 614 

P.2d 516. 

There is no dispute that Nelson suffers from spinal stenosis. 

Furthemore, the doctors agree that had the original injury and the 

resulting fusion surgery never occurred, it is unlikely that Nelson 

would have ever developed spinal stenosis. There is evidence, 

although the doctors dispute whether it is merely possible or 
whether it is probable, that strenuous physical activity 

accelerates hypertrophic bone growth and the development of spinal 

stenosis. It was not possible for the physicians to determine if 

the stenosis developed prior to or after Nelson began working for 

Semitool. However, there is evidence that Nelson continued to have 

back problems in the years immediately preceding his work with 

Semitool. 

Nelson contends that because his preexisting condition did not 

prevent him from working at Semitool it is not a disability that 

permits apportionment. Furthermore, he contends that the 

occupational disease from which he suffers is spinal stenosis, a 

distinct and separate condition from the original postal service 

injury that required the fusion surgery. Nelson refers to Larsen's 

treatise on Workers' Compensation wherein Larsen states: 

To be apportionable, then, an impairment must have been 

independently producing some degree of disability before 

the accident, and must be continuing to operate as a 

source of disability after the accident, Larsen ' s 

Workers' Compensation, Volume 2, Section 59.22(c), Page 

10-401. 

We do not find the conclusion of the Workers' Compensation Court to 

be inconsistent with Larsen as cited above. There is substantial 

evidence that the original back injury was an impairment that 

"independently produced some degree of disability". For example, 

claimant had to leave a previous job due to his back injury. There 

is also substantial evidence to support the finding that the prior 

injury is the source of Nelson's current disability. 

Section 39-72-706, MCA, requires that if a disability from 
another cause is aggravated or accelerated or in any way 

contributed to by an occupational disease, compensation for the 

occupational disease is reduced in a proportional amount. We 

conclude that substantial evidence exists that cumulative trauma 

from work at Semitool aggravated Nelson's preexisting back 

disability. The Workers' Compensation Court is affirmed. 

r7' 

i/ We Concur : ,,* 
March 

CERTIFICATE 

1 hereby certify that the following order w; 

following named: 

Kenneth E. O'Brien 

Hash, O'Brien & Bartlett 

P.O. Box 1178 

Kalispell, M'T 59903 

I, 1992 

OF SERVICE 

gent by Unitcd States mail, prepaid, to the 

Robert E. Sheridan 

Garlington, hhn & Robinson 

P.0. Box 7909 

Missoula, MT 59807 

ED SMITH 

CLERK OF THE SUPREME COIJRT 

STATE OF MONTANA