Lanes v. Montana State Fund, 2008 MT 306, 346 Mont. 10, 192 P.3d 1145 The aggravation provision is a reflection of the long-standing rule that employers take their workers as they find them and that a traumatic event or unusual strain which lights up, accelerates, or aggravates an underlying condition is compensable. However, case law has established that an aggravation must be “significant” before it will be considered the last injurious exposure. Where Petitioner and his treating physician both testified that his job duties as a minister only temporarily aggravated his pre-existing knee condition, this does not constitute the last injurious exposure.

[1999] Montana State Fund v. Murray, 2005 MT 97 (No. 04-576) Where claimant alleges an occupational exposure worsened a preexisting condition and led to benefit entitlement, the test for compensability under the Occupational Disease Act is whether occupational factors significantly aggravated the preexisting condition, not whether there was a “substantial” aggravation.

[1993] Polk v. Planet Insurance Co., 287 Mont. 79, 951 P.2d 1015 (1997) In light of the occupational disease proximate cause requirement, set out at section 39-71-408, MCA, and the aggravation statute, section 39-71-706, MCA, occupational aggravations of preexisting non-occupational diseases are compensable, as are occupational diseases which are aggravated by non-occupational factors. The test for compensability under the OD Act is whether occupational factors significantly aggravated a preexisting condition, not whether occupational factors played the major or most significant role in causing a particular disease. As long as an occupational exposure substantially aggravated a pulmonary condition, claimant is entitled to pro rata compensation for his disease. The DOL hearing examiner, and the WC Court, erred in basing their decision on medical opinions by physicians who operated under the mistaken assumption that occupational irritants had to be the major factor causing a pulmonary condition for claimant to receive compensation.

[1999] State Fund v. Carl Murray [4/6/04] 2004 MTWCC 33 The fact that the claimant's recreational activities may have contributed to his preexisting bilateral knee condition does not preclude a finding of an occupational disease where the evidence establishes that the claimant's work significantly and materially aggravated his underlying condition. Affirmed Montana State Fund v. Murray, 2005 MT 97

[1999] State Fund v. Carl Murray [4/6/04] 2004 MTWCC 33 The Montana Occupational Disease Act does not require that occupational exposures be the principal or substantial cause of the condition, only that the "occupational factors significantly aggravated a preexisting condition." § 39-72-408, MCA (1971-1999); Polk v. Planet Ins. Co., 287 Mont. 79, 951 P.2d 1015 (1997). Affirmed Montana State Fund v. Murray, 2005 MT 97

[1999] State Fund v. Carl Murray [4/6/04] 2004 MTWCC 33 Aggravations of preexisting conditions are compensable under the Montana Occupational Disease Act. § 39-72-706, MCA (1989-2003). Affirmed Montana State Fund v. Murray, 2005 MT 97

[1995] Baumgartner v. Liberty NW [4/14/97] 1997 MTWCC 19 Although it would take little more than three years for occupational disease claimant's wage loss to reach $10,000, meaning he would ordinarily qualify for the maximum indemnity award under section 39-72-405, MCA (1995), the Court applied the apportionment provisions of section 39-72-706, MCA (1995) to an award under section 405. Where medical evidence attributed only 60% of the causation of claimant's low back condition to work, he was awarded $6,000.

[1993] Boldosser v. State Fund [6/10/96] 1996 MTWCC 42 Aggravations of preexisting conditions or diseases are compensable under the ODA.