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                                     Appellate Court                         Date: 2017.07.24
                                                                             10:58:43 -05'00'




        Simpson v. Illinois Workers’ Compensation Comm’n, 2017 IL App (3d) 160024WC



Appellate Court          CURTIS SIMPSON, Appellant, v. THE ILLINOIS WORKERS’
Caption                  COMPENSATION COMMISSION (City of Peoria, Appellee).



District & No.           Third District
                         Docket No. 3-16-0024WC



Filed                    April 18, 2017



Decision Under           Appeal from the Circuit Court of Peoria County, No. 15-MR-78; the
Review                   Hon. James Mack, Judge, presiding.



Judgment                 Affirmed.


Counsel on               Robert W. Bach, of Peoria, for appellant.
Appeal
                         Boyd O. Roberts III and Kyle M. Tompkins, of Hasselberg, Grebe,
                         Snodgrass, Urban & Wentworth, of Peoria, for appellee.

                         Thomas W. Duda, of Law Offices of Thomas W. Duda, of Palatine,
                         for amicus curiae Associated Fire Fighters of Illinois.

                         Jessica E. DeWalt, of Illinois Municipal League, of Springfield,
                         amicus curiae.
     Panel                    JUSTICE MOORE delivered the judgment of the court, with opinion.
                              Justices Hoffman, Hudson, and Harris concurred in the judgment and
                              opinion.
                              Presiding Justice Holdridge dissented, with opinion.


                                               OPINION

¶1         The claimant, Curtis Simpson, appeals the judgment of the circuit court of Peoria County,
       which confirmed the decision of the Workers’ Compensation Commission (Commission) to
       deny him benefits under section 8 of the Workers’ Compensation Act (Act) (820 ILCS 305/8
       (West 2014)), which he sought against his employer, the City of Peoria (City). In addition,
       the following motions have been taken with the case on appeal: (1) the City’s motion to
       strike the amicus curiae brief filed by the Associated Firefighters of Illinois (AFFI) on behalf
       of the claimant and (2) the motion of the Illinois Municipal League (IML) for leave to
       intervene as amicus curiae and to file a brief on behalf of the City. For the following reasons,
       we grant the City’s motion to strike as to those portions of the AFFI’s brief that contain or
       reference matters that are de hors the record, grant IML’s motion to intervene as amicus,
       deeming its brief to be filed instanter, and affirm the judgment of the circuit court, which
       confirmed the decision of the Commission.

¶2                                                FACTS
¶3         The claimant was employed by the City as a firefighter. On May 21, 2008, the claimant
       filed an application for adjustment of claim under the Act (820 ILCS 305/1 et seq. (West
       2008)), alleging work-related permanent injury to his heart by virtue of a heart attack. An
       arbitration hearing was held on March 19, 2014, in which the claimant amended his
       application to designate the injury as “heart attack and cardiovascular disease.” The
       following evidence was adduced at the arbitration hearing.
¶4         The claimant testified that he began employment with the City as a beginning
       firefighter/hoseman in 1976. He served as a front line or line of duty firefighter for
       approximately 22 years, and testified in detail regarding his extensive history of exposure
       with regard to fire, smoke, and other toxins; his demolition of buildings; high-stress
       situations; and noise. He also testified that when he became a fireman, protective equipment
       was not available, but it progressively became more available as time went on.
¶5         The claimant testified that he became an administrative officer for the City’s fire
       department in 1997 and worked in this capacity until the end of his career. In his first
       administrative positions, such as Assistant Chief, he was not as closely related to the fire and
       basic life support calls in terms of his day-to-day activities in that he was only required to
       respond to multi-alarm fires. However, he testified that there was a lot of stress involved
       when he became Battalion Chief and became responsible for the safety of 60 firefighters
       throughout an entire 24-hour period. In that position, he had to respond to all working fires.
¶6         The claimant testified that on January 12, 2008, at the age of 63, he was home sweeping
       and cleaning his garage. After he finished, he went into the house to take a shower and get
       ready for dinner. After his shower, he felt some moderate pain and lay down on the bed to


                                                  -2-
       rest. His girlfriend at the time, who is now his wife, came and asked him what was wrong.
       Although the pain was not debilitating, she insisted he go to the hospital. He was treated at
       the emergency room of Proctor Hospital by a cardiologist, Darrel Gumm, who diagnosed
       cardio enzyme elevation and then heart attack. Following that, he underwent an angiogram
       and the placement of two stents. He was placed on several medications: Atenolol, Lisinopril,
       sodium vasolate, and Plavix, which is a blood thinner. He soon learned that taking a blood
       thinner such as Plavix disqualified him from working in any capacity at the City fire
       department.
¶7          The claimant testified that he did not have a family history of cardiovascular disease, had
       never been a smoker, and his alcohol use was minimal. As a result of his heart attack, he
       applied for a duty disability pension, which was granted. Since that time, he has had
       cardiovascular treatment in the form of cardiac rehabilitation services and had a third stent
       placement by Dr. Gumm in 2009. Due to his cardiovascular condition, he no longer engages
       in stressful activities or a regimented exercise program for fear of having another heart
       attack.
¶8          On cross-examination, the claimant testified that in addition to the traumatic experiences
       he went through as a firefighter, there were many positive outcomes and good things that
       happened while he was working, such as saving lives. During the course of his career as a
       firefighter, he never sought mental health treatment or psychological counseling. The stress
       of the job never got to the point that he needed medical intervention or felt it was affecting
       his ability to do his job or perform the everyday activities of his life.
¶9          Once he moved into an administrative capacity in 1997 for the City, the requirement that
       he physically enter a burning building was significantly diminished. In addition, his hours
       changed from 24 hours on, 48 hours off, to a standard 8 a.m. to 5 p.m., 40 hours-per-week
       schedule. However, every other month he would be on call as the Division Chief to respond
       to all working fires.
¶ 10        At the time of his heart attack, the claimant was on medication for hypertension (high
       blood pressure) and hyperlipidemia (high cholesterol). He had been tested for sleep apnea but
       the test was negative, although certain medical records report a history of sleep apnea. His
       mother also had a history of hypertension, although the medical records indicate that the
       claimant, at some point in time, reported a history of heart disease in his mother. The
       claimant characterized himself as overweight at the time of the heart attack, having been in
       more of a sedentary job. While cleaning his garage on the day of his heart attack, he moved
       half a bag of bird seed out of the way and rolled a cart with more bird seed as well. He now is
       retired, lives in Arizona, and has regular stress tests under the care of a cardiologist but is not
       under any physical restrictions from any doctor.
¶ 11        The evidence deposition of Dr. Virginia Weaver was admitted into evidence on behalf of
       the claimant. Dr. Weaver testified regarding a vast array of credentials, the most relevant
       being that she is a doctor of public health at the Bloomberg School of Public Health at Johns
       Hopkins University. She is board certified in internal medicine and occupational medicine.
       She is a member of the American College of Occupational and Environmental Medicine and
       serves on the medical advisory board of the International Association of Firefighters (IAFF).
¶ 12        Dr. Weaver testified that she prepared a report concerning the claimant at the claimant’s
       attorney’s request. In preparation for her report, dated September 9, 2013, Dr. Weaver
       reviewed the claimant’s medical records from his emergency room admission and subsequent

                                                    -3-
       cardiac treatment; the report and deposition of the City’s expert, Dr. Fintel; and the report of
       Dr. McDowell, a resident of the IAFF, who assisted Dr. Weaver in the evaluation of the
       claimant’s condition and its cause. Dr. Weaver testified that she also conducted a phone
       interview with the claimant.
¶ 13        Dr. Weaver testified that she spoke with the claimant in order to get an understanding of
       his working career and specific issues within his job that could have resulted in exposure to
       any of the number of firefighting hazards that can result in cardiovascular disease. She
       testified that the claimant’s work history is consistent with most firefighters in the United
       States in that, during the first two to three years of his employment as a firefighter, he
       generally did not use any type of breathing apparatus during fire suppression and overhaul
       activities. Following that, he began using self-controlled breathing apparatus (SCBA)
       equipment during active fire suppression but not during the overhaul phase. In the last couple
       of decades, the data shows that overhaul activities are as high-risk as fire suppression
       activities, and it is recommended now that firefighters keep their SCBA equipment on the
       entire time they are doing suppression and overhaul.
¶ 14        Dr. Weaver testified that as a result of the multiple times the claimant undertook fire
       suppression activities without SCBA equipment, the claimant had extensive exposure to
       chemical asphyxiates, such as carbon monoxide and cyanide. In addition, Dr. Weaver
       testified that the claimant’s stress and noise exposure during his 22 years of active
       firefighting was extensive and that this type of occupational stress is a risk factor for heart
       disease. Dr. Weaver testified that the claimant’s history of hypertension “can certainly be
       occupational as a firefighter and non-occupational.” She recognized that the claimant’s
       obesity, age, sex, and history of hyperlipidemia were also risk factors but that chronic
       occupational exposure from firefighting in terms of chemicals, stress, noise, and disrupted
       sleep were risk factors as well.
¶ 15        Dr. Weaver explained recent developments regarding occupational hazards related to
       firefighting and cardiovascular disease. It has been very clear for a long period of time that
       acute exposure to certain chemical asphyxiates during fire suppression activities followed by
       a cardiac event within 24 to 48 hours signifies a work-related injury. However, there is now
       literature that shows that chronic carbon monoxide exposure increases the risk of
       hypertension and elevated blood levels of inflammatory markers which are risk factors for
       subsequent cardiac disease. Other potential mechanisms for cardiovascular disease from
       chronic smoke exposure include increased formation of free radicals, subsequent endothelial
       dysfunction, increased coagulability of the blood, and increased progression of
       atherosclerosis. In addition, shift work involving sleep deprivation has now been correlated
       with hypertension, diabetes, obesity, and heart disease. Chronic noise and stress are also
       associated with an increased risk for chronic hypertension. Dr. Weaver concluded that the
       claimant had 31 years of exposure to these chronic risk factors and that it is therefore her
       opinion, within a reasonable degree of medical certainty, that his occupation may have been a
       cause of his cardiovascular disease and myocardial infarction.
¶ 16        On cross-examination, Dr. Weaver testified that she is not board certified in
       cardiovascular disease, critical care medicine, or nuclear cardiology. The IAFF has had a
       long-standing contractual relationship with the Bloomberg School of Public Health, where
       she is Director of the Occupational and Environmental Medicine Residency. Funds are
       transferred to the school to provide salary support for faculty to oversee residents rotating at

                                                  -4-
       IAFF to assist with questions of causation with regard to injuries in firefighters. The main
       focus of her practice in this position is to provide causation expertise for firefighters with
       about 5 to 10 percent of her practice devoted to treating patients. She does not treat patients
       with cardiovascular disease.
¶ 17       With regard to specific exposures, Dr. Weaver testified that benzene, carbon monoxide,
       hydrogen cyanide, asbestos, P.A.H.’s, formaldehyde, carbon disulfide, diesel exhaust, and
       soot are routinely reported at fires where monitoring has been done. However, specific
       information about which of these chemicals a firefighter has been exposed to over the course
       of his or her career and in what amounts is almost never available, making exposure
       assessment extremely difficult for research purposes. This is true in the case of the claimant
       as well.
¶ 18       The claimant also introduced records from his line of duty disability pension examination
       into evidence. According to an independent medical disability report prepared by Dr. Robert
       Ayers at the Occupational Health Foundation on April 30, 2008, the claimant had been
       evaluated 30 years prior to the exam with coronary angiography for chest pain. He was
       diagnosed as having coronary spasm and his angiogram was normal at that time. It was his
       impression that it was marital stress related. He was not given any medications and had no
       recurrence. The report noted that the claimant had been treated for high blood pressure and
       elevated cholesterol for several years also.
¶ 19       Regarding the incident at issue in this case, the report indicated that the claimant
       presented to the Proctor Emergency Room for chest pain on January 12, 2008. His blood
       enzymes changed, and he was diagnosed as having a heart attack. He was seen by Dr.
       Gumm, who performed a coronary angiography and he had two stents placed and “has done
       okay since then.” He had no recurrent chest pain as of that date. Regarding occupational
       history, it was noted that at the time of the injury, the claimant was the Assistant Fire Chief
       for the City. He had been employed there for 31 years. He performed administrative work
       with occasional physical work. He was a front line firefighter for 22 years. He was advised
       by the Chief that because he is taking Plavix, he is not able to do firefighting work. With
       regard to whether the claimant’s disability was caused by an on-the-job incident, the report
       noted that the claimant was cleaning his garage at the time preceding the incident. However,
       the report noted that, based upon legislation passed in Illinois, taking effect January 1, 2008,
       firefighters are included in the designation that would allow them to claim work relatedness
       to any heart problems. The report concluded that the statute would allow this to be rebutted
       in a legal setting.
¶ 20       Finally, the claimant introduced a pension board examination report prepared by Dr. M.
       Fayez Malik of Heartcare Midwest on May 1, 2008. Dr. Malik’s impressions of the claimant
       included: coronary artery disease post-stenting with no evidence of angina or failure at that
       time but with moderate disease in the other vessels which was being actively followed by Dr.
       Gumm at that time with risk factor modifications; hypertension with blood pressure slightly
       elevated at the time of the report; and hyperlipidemia with an improving lipid profile. Dr.
       Malik recommended that the claimant follow up with Dr. Gumm with a pre-office visit stress
       test to reassess the stented vessels and other territories, continue to take medications as
       instructed, limit salt intake, and check blood pressure at home.
¶ 21       Exhibits were admitted into evidence on behalf of the City. First, the job descriptions
       regarding the administrative positions the claimant held during the final nine years of his

                                                  -5-
       career were admitted into evidence. The claimant’s most recent position of Assistant Fire
       Chief is summarized as an assistant to the fire chief in the administration and direction of the
       fire department—overseeing, coordinating, and reviewing the activities and staff of three
       divisions within the department. A review of the list of essential job functions for this
       position reveals a host of administrative responsibilities. However, essential job functions
       include serving as incident commander at large emergency scenes. In addition, working
       conditions are listed as occasional exposure near fumes or airborne particles and extremely
       hazardous, life threatening environments at emergency scenes.
¶ 22       With regard to the claimant’s prior administrative position of Fire Division Executive,
       essential job functions were heavy in administrative work. However, job functions also
       included responding to and managing emergency scenes through the implementation of an
       incident command system as assigned. With regard to working conditions, the job description
       states that while performing the essential functions of this position, the employee is
       frequently exposed to wet and humid conditions, fumes or airborne particles, extreme cold,
       and extreme heat. In addition, the employee is occasionally exposed to toxic or caustic
       chemicals, work in high precarious places, and work with explosives, with irregular hours
       and shift times. The working conditions for this position are typically moderately quiet unless
       on an emergency scene, then the conditions are typically loud.
¶ 23       With regard to Battalion Chief, the claimant was charged with assuring the protection of
       lives and property through supervision of all employees during normal operations. Job
       functions included a host of administrative duties, but also included command and control of
       multi-unit response to fire, rescue, and emergency scenes; investigation and reporting of all
       vehicular accidents involving fire apparatus or personnel while on duty; and direction and
       possible assistance with the extrication of persons from car accidents and other entrapments.
       The position description specifies that while performing the essential functions of this
       position, the employee is frequently exposed to flames, smoke, extreme hot or cold
       conditions, work in high precarious places, hazardous materials, risk of electrical shock, and
       violent and uncontrollable individuals. The description also states that working time may
       require irregular hours and shift times and frequently loud working conditions.
¶ 24       The claimant’s work history records with the City reflect that he was hired as a firefighter
       on August 30, 1976. The record includes some gaps in time as far as the claimant’s service
       but shows that he worked four years as a hoseman, took a six-month leave of absence for
       military training, and worked until at least 1993 as a front line firefighter, with some time
       periods serving as fire engineer as well. The first record of his service in an administrative
       capacity shows a date of 2004, and it appears he served as Fire Division Executive for two
       years, followed by Assistant Fire Chief for three years. There is not a record of the claimant
       serving as Battalion Chief included in the exhibit, although the claimant clearly testified to
       serving in that position.
¶ 25       The City introduced an independent medical evaluation (IME) report on the claimant,
       conducted by Dr. William S. Scott at St. Francis Medical Center on July 15, 2008, at the
       request of the Firemen’s Pension Fund of Peoria. Of relevance to this appeal, Dr. Scott
       opined that based on his personal risk factors, non-work location, and activities at the time of
       the cardiac event, the claimant’s condition was not caused by an on-the-job incident. Dr.
       Scott stated that the claimant has coronary artery disease associated with personal risk factors
       and a coronary event at home while doing strenuous activities. Dr. Scott determined that the

                                                  -6-
       claimant seems to have the same general risk factors as the regular population of people with
       coronary artery disease and that it is known that “other men with similar personal risk factors
       in different occupations or even in no occupations can experience similar events.” Dr. Scott
       concluded that “it would appear to be not medically valid to assume his cardiac event
       occurred solely due to his occupation as a firefighter while ignoring valid risk factors of age,
       sex, hyperlipidemia, [and] long history of hypertension.”
¶ 26       The report and evidence deposition of Dr. Dan Fintel of the Cardiology Division of The
       Feinberg School of Medicine at Northwestern University was admitted into evidence on
       behalf of the City. Dr. Fintel conducted a record review regarding the claimant. Dr. Fintel’s
       report states as follows:
               “I do not believe the patient-reported history of coronary vasospasm in the 1980s
               contributes to [the claimant’s] risk for the cardiac event on 1/12/08. Relevant medical
               records to substantiate this report are not available for review. The Proctor Hospital
               angiogram dated 1/14/08 definitively identifies multi-vessel atherosclerotic coronary
               artery disease, with an obstructive lesion in the right coronary artery. Coronary
               angiography is the gold standard study to establish the diagnosis of coronary artery
               disease. Extensive coronary disease, like that identified in [the claimant], is due to the
               interplay of non-modifiable genetic predisposition and lifestyle factors such as diet,
               exercise, and habits. While the acute rupture of a coronary cholesterol plaque can be
               related to hormone surges during severe physical and emotional stressors, this is not
               the type of process indicated in the angiogram or the clinical history at [the
               claimant’s] presentation. The [claimant’s] risk factors for the development of
               coronary disease included age, male sex, hypertension, hyperlipidemia, and obesity.
                   [The claimant’s] cardiac symptoms occurred while the patient was at home, off
               duty, and performing physical labor on his own accord. These symptoms are best
               described by Dr. Dhanekula, whose history dated 1/13/08 indicates that the chest
               discomfort came on in the shower after [the claimant] was working in his garage with
               heavy items. As such, I do not believe the cardiac event was caused or precipitated by
               his work as a firefighter. The evidence in the medical record, namely [the claimant’s]
               documented risk factors, presenting clinical history, and angiographic findings,
               strongly suggest that the event of 1/12/08 was due to the progression of coronary
               atherosclerosis (narrowing of the arteries), which in turn was the result of underlying
               risk factors.” (Emphases in original.)
¶ 27       During his deposition, Dr. Fintel testified extensively regarding his credentials in the area
       of cardiovascular disease and treatment, including board certifications in cardiovascular
       diseases, critical care medicine, and nuclear cardiology. About 80% of his time on the staff at
       Northwestern entails attending to patients in the coronary care unit, the observation unit
       where he admits patients with suspected cardiac conditions, and the consultation service
       where he performs cardiac consultations. He also attends a busy outpatient cardiac practice in
       the clinic building. Academically, he oversees residents, lectures at Northwestern and all
       over the world, and publishes between one and three articles or book chapters per year in
       various texts. In the medical/legal consultation arena, Dr. Fintel testified that he does about
       two-thirds of his work on behalf of defendants and one-third on behalf of plaintiffs.
¶ 28       Dr. Fintel testified consistently with his record review report. In addition, in the
       deposition, Dr. Fintel was asked whether he had an opinion based upon a reasonable degree

                                                   -7-
       of medical and surgical certainty as to whether the claimant’s cardiac event could have been
       caused by his employment as a firefighter. In response, Dr. Fintel stated:
               “My opinion is that in the presence of these significant risk factors for coronary artery
               disease, the hypertension, hyperlipidemia, mild family history, male sex, that [the
               claimant] was the essential kind of powder keg waiting to explode, that is, that he had
               risk factors for coronary disease that were the cause of his atherosclerosis, and that
               the events that occurred while working in his garage on January 12, 2008[,] were a
               culmination of that process, and the mild heart attack that resulted was a direct
               correlate or consequence of his risk factors leading to his underlying coronary
               disease.”
¶ 29        On cross-examination, Dr. Fintel testified that atherosclerotic process is not fully
       understood, but the risk factors he outlined earlier increase the probability that it will
       develop. He agreed that given the evidence of coronary heart disease found in the claimant at
       the time of his heart attack, it would be fair to say that coronary artery disease had been
       present for a substantial period of time prior to 2008. He testified that he reviewed no records
       and had no knowledge of the particular duties the claimant performed as a firefighter.
¶ 30        On May 2, 2014, the arbitrator issued a decision awarding the claimant PPD benefits
       pursuant to section 8(d)(2) of the Act (820 ILCS 305/8(d)(2) (West 2008)), representing 25%
       loss of use of the whole person. The City sought review before the Commission, which
       issued its decision on January 20, 2015. Finding that the application of section 6(f) of the Act
       (820 ILCS 305/6(f) (West 2008)) presents a case of first impression, the Commission turned
       to the Illinois Supreme Court’s decision in Franciscan Sisters Health Care Corp. v. Dean, 95
       Ill. 2d 452, 460-63 (1983), for guidance as to the analysis to be employed to determine
       whether a legislative presumption has been rebutted. Employing “Thayer’s bursting-bubble
       hypothesis,” which posits that once sufficient evidence is produced “ ‘to support a finding of
       the nonexistence of the presumed fact,’ ” the presumption ceases to operate and the issue is
       determined as if no presumption ever existed, the Commission first considered the amount of
       evidence needed to rebut the presumption created by section 6(f) of the Act. Id. at 462-63
       (citing McCormick’s Handbook of the Law of Evidence § 345, at 821 (Edward W. Cleary
       ed., 2d ed. 1972), and quoting Michael H. Graham, Presumptions in Civil Cases in Illinois:
       Do They Exist?, 1977 S. Ill. U. L.J. 1, 24). Noting that the presumption applicable in this case
       is a legislative one, the Commission determined that it requires “stronger evidence” to
       overcome.
¶ 31        Turning to the case at bar, the Commission found that the City had successfully rebutted
       the presumption that the claimant’s cardiovascular disease was causally related to his
       employment as a firefighter “by providing strong evidence through its experts’ opinions
       along with [the claimant’s] own health history, work history and [the claimant’s] own
       testimony to show there were other causes of [the claimant’s] cardiovascular problems and
       his condition is not related to his employment as a firefighter.” Finding the presumption to be
       successfully rebutted, the Commission weighed the evidence to determine whether the
       claimant met his burden to prove by a preponderance of the evidence that his “heart attack”
       was related to his employment with the City. The Commission found that the claimant failed
       to meet his burden because at the time of his heart attack, he was at home, had just physically
       exerted himself, and was not performing any activity connected to his duties as a firefighter
       or Assistant Fire Chief. In addition, the Commission found that during the last one-third of

                                                   -8-
       his career, the claimant was working in an administrative capacity, performing tasks of a
       more sedentary nature, and had several cardiac risk factors, including being a male of
       advanced age, overweight, and on medications for high blood pressure and high cholesterol.
       The Commission also noted that the claimant had a poor diet and family history of
       hypertension. Due to the extent of his atherosclerotic disease, the Commission found credible
       Dr. Fintel’s opinion that the claimant was essentially “a powder keg waiting to explode” and
       found Dr. Fintel’s opinion, as well as those of Drs. Scott and Ayers, to be more credible than
       that of Dr. Weaver. As such, the Commission found that the claimant failed to meet his
       burden of proof and that his claim is not compensable.
¶ 32       The claimant sought review of the Commission’s decision before the circuit court of
       Peoria County. On December 17, 2015, the circuit court entered an order confirming the
       decision of the Commission. On January 7, 2016, the claimant filed a notice of appeal with
       this court. On May 23, 2016, AFFI filed a motion for leave to file a brief as amicus curiae on
       behalf of the claimant. The City filed no response to the motion, and on June 8, 2016, this
       court entered an order allowing the amicus curiae brief. On June 17, 2016, the City filed a
       motion to strike the amicus curiae brief and AFFI requested leave to respond to the motion to
       strike. On July 27, 2016, this court entered an order allowing AFFI to respond to the motion
       to strike and taking the motion with the case.
¶ 33       On October 17, 2016, after this case had been fully briefed and placed on the call of the
       docket for December 8, 2016, IML filed a motion to intervene as amicus curiae and to file a
       brief in support of the City. IML acknowledged that the date for filing an amicus brief was
       long past due but argued that the parties to this matter will not be unfairly prejudiced by the
       granting of the motion and that it was not informed by the City that the AFFI submitted an
       amicus brief until September 1, 2016. IML claimed in its motion that its interest in this case
       is substantial because the claimant’s claim “threatens hundreds of the League’s municipal
       members and their citizenry,” and this court’s decision “will substantially increase the burden
       on municipalities if they will be required to pay workers’ compensation claims for injuries to
       the administrative staff of fire departments that do not arise out of and in the course of
       normal employment.” On October 21, 2016, this court entered an order taking IML’s motion
       with the case and requiring IML to file its proposed amicus curiae brief within seven days.
       On October 31, 2016, this court received IML’s proposed amicus brief.

¶ 34                                           ANALYSIS
¶ 35      We begin by considering the City’s motion to strike the amicus curiae brief filed by
       AFFI. Illinois Supreme Court Rule 345(a) (eff. Sept. 20, 2010) provides as follows:
              “A brief amicus curiae may be filed only by leave of the court or of a judge thereof,
              or at the request of the court. A motion for leave must be accompanied by the
              proposed brief and shall state the interest of the applicant and explain how an amicus
              brief will assist the court.”
¶ 36      On May 23, 2016, AFFI filed a motion pursuant to Rule 345(a), along with a copy of the
       proposed brief and affidavit of AFFI President Pat Devaney, in which he averred that the
       AFFI assisted in drafting, presenting, and arguing House Bill 928, which culminated in the
       enactment of section 6(f) of the Act. 820 ILCS 305/6(f) (West 2008). According to paragraph
       one of the City’s motion to strike, it appears that the City received a copy of the motion and
       proposed brief as per the certificate of service attached to AFFI’s motion. The City did not

                                                  -9-
       file an objection to AFFI’s motion, despite having notice of the brief’s contents prior to this
       court’s order of June 8, 2016, granting the motion. Instead, the City filed a motion to strike
       the brief on June 17, 2016, which this court ordered to be taken with the case. Having
       considered the City’s motion, AFFI’s response thereto, and the City’s reply, we grant the
       motion to strike as to any material contained or referenced in AFFI’s brief that are de hors
       the record. See Zurich Insurance Co. v. Raymark Industries, Inc., 118 Ill. 2d 23, 60 (1987)
       (striking briefs of amicus curiae that relied upon materials that were not part of the record on
       appeal).
¶ 37        We next consider the motion of the IML to intervene as amicus curiae and to file a brief
       on behalf of the City. Illinois Supreme Court Rule 345(b) (eff. Sept. 20, 2010), which
       governs the timing for filing of a brief of an amicus curiae, provides that “[u]nless the court
       or a judge thereof specifies otherwise, it shall be filed on or before the due date of the initial
       brief of the party whose position it supports.” Having received IML’s proposed amicus brief,
       and in the interest of giving full consideration to all interested parties in this case of first
       impression, this court grants IML’s motion to file its amicus brief out of time.
¶ 38        Turning to the merits of the claimant’s appeal, we begin our analysis by making a
       determination of the applicable standard of review. The standard of review, which determines
       the level of deference to be afforded the Commission’s decision, depends on whether the
       issue presented on appeal is one of fact or one of law. See Johnson v. Illinois Workers’
       Compensation Comm’n, 2011 IL App (2d) 100418WC, ¶ 17. Our review of the
       Commission’s factual findings is limited to determining whether such findings are against the
       manifest weight of the evidence. Id. A finding of fact is against the manifest weight of the
       evidence only where the opposite conclusion is clearly apparent. Beelman Trucking v. Illinois
       Workers’ Compensation Comm’n, 233 Ill. 2d 364, 370 (2009). “Commission rulings on
       questions of law are reviewed de novo.” Johnson, 2011 IL App (2d) 100418WC, ¶ 17. “We
       also apply a de novo standard of review when the facts essential to our analysis are
       undisputed and susceptible to but a single inference, and our review only involves an
       application of the law to those undisputed facts.” Id.
¶ 39        Here, in accordance with the above-stated principles, the propriety of the Commission’s
       decision presents us with two separate inquiries involving two separate standards of review.
       The first issue on appeal involves the interpretation of section 6(f) of the Act (820 ILCS
       305/6(f) (West 2008)) and a determination as to whether the Commission properly applied
       the rebuttable presumption set forth therein. This is an issue of law for which our standard of
       review is de novo. See Johnson, 2011 IL App (2d) 100418WC, ¶ 17. The second issue
       requires us to determine the propriety of the Commission’s ultimate determination that the
       claimant’s condition of ill-being was not causally related to his employment as a firefighter.
       This issue mandates that we confirm the Commission’s decision unless it is against the
       manifest weight of the evidence. See id.
¶ 40        Having determined the appropriate standards of review to be employed in this case, we
       turn to section 6(f) of the Act, which provides, in relevant part, as follows:
               “Any condition or impairment of health of an employee employed as a firefighter ***
               which results directly or indirectly from any *** heart or vascular disease or
               condition, [or] hypertension *** resulting in any disability (temporary, permanent,
               total, or partial) to the employee shall be rebuttably presumed to arise out of an in the
               course of the employee’s firefighting, *** and, further, shall be rebuttably presumed

                                                   - 10 -
               to be causally connected to the hazards or exposures of the employment. ***
               However, this presumption shall not apply to any employee who has been employed
               as a firefighter *** for less than 5 years at the time he or she files an Application for
               Adjustment of Claim concerning this condition or impairment with the Illinois
               Workers’ Compensation Commission.”1 820 ILCS 305/6(f) (West 2008).
¶ 41       Turning to the first issue on appeal, which requires us to make a legal determination
       regarding the application of section 6(f), we begin by addressing the issue raised by IML in
       its amicus brief, that the claimant is not a firefighter for purposes of section 6(f) because he
       served in an administrative capacity as Assistant Fire Chief at the time of his heart attack and
       was not actively engaged in firefighting. This issue was not raised by the parties below. At no
       time has the City disputed that the claimant is a firefighter.
¶ 42       The Commission found that the petitioner was a firefighter at the time of his heart attack,
       a finding that we cannot say is against the manifest weight of the evidence because an
       opposite conclusion is not clearly apparent. See Beelman Trucking, 233 Ill. 2d at 370. The
       claimant served as a front line firefighter for 22 years, followed by service in managerial
       capacities for the 11 years prior to his heart attack, during the latter of which he did, at times,
       respond to the scenes of fires to coordinate firefighting efforts. For these reasons, we find
       that the claimant’s occupation does fall within the auspices of section 6(f).
¶ 43       While we recognize the IML’s concerns that applying the presumption to the claimant in
       this case “will substantially increase the burden on municipalities if they will be required to
       pay workers’ compensation claims for injuries to the administrative staff of fire
       departments,” this court is simply enforcing the statute as written based on the record before
       us, and it is outside of our province to rewrite the presumption as it pertains to firefighters
       who have worked their way through the ranks of a fire department to managerial positions.
¶ 44       The evidence is also undisputed that the claimant suffered a heart attack and has an
       underlying atherosclerotic disease, which contributed to this injury, both of which are
       directly related to a heart or vascular disease or condition. Accordingly, pursuant to section
       6(f), the claimant’s condition is rebuttably presumed to arise out of and in the course of the
       claimant’s firefighting and to be causally connected to the hazards or exposures of
       firefighting. 820 ILCS 305/6(f) (West 2008). As such, the issue becomes whether the
       Commission properly applied the presumption. Concurrent with our taking the present case
       under advisement, this court was asked to determine the application of this presumption in
       Johnston v. Illinois Workers’ Compensation Comm’n, 2017 IL App (2d) 160010WC. In the
       Johnston opinion, we set forth in detail how the presumption is to be applied, and our
       analysis and holding in Johnston is directly applicable to the case at bar.
¶ 45       This Court in Johnston adopted Thayer’s bursting bubble hypothesis, which was
       referenced in the decision of the Commission in the case at bar. Id. ¶¶ 36-37 (citing
       Diederich v. Walters, 65 Ill. 2d 95, 100-01 (1976)). This theory regarding the effect of a
       rebuttable presumption posits that “ ‘once evidence opposing the presumption comes into the
       case, the presumption ceases to operate, and the issue is determined on the basis of the

           1
            We note that this language was added to section 6 of the Act (820 ILCS 305/6(f) (West 2008)) by
       Public Act 95-316 (eff. Jan. 1, 2008). Accordingly, the language set forth later in this section, which
       states that “[t]he changes made to this subsection by Public Act 98-291 shall be narrowly construed,”
       does not apply to the statutory language at issue in this appeal. 820 ILCS 305/6(f) (West 2014).

                                                     - 11 -
       evidence adduced at trial as if no presumption had ever existed.’ ” Id. ¶ 36 (quoting
       Diederich, 65 Ill. 2d at 100-01, citing 1 Spencer A. Gard, Jones on Evidence § 3:8 (6th ed.
       1972)). In determining the amount of evidence required to terminate the operation of the
       presumption, this court set forth a detailed analysis of the differing standards that are applied
       depending on the origin of the presumption. See id. ¶¶ 39-40. In a case such as this, where
       there is a statutory presumption, and the statute is silent as to the amount of evidence
       required, we found that principles of statutory interpretation and, specifically, a review of its
       legislative history, was required to determine the legislature’s intent. Id. ¶ 43.
¶ 46       After a detailed analysis of the legislative history of section 6(f) of the Act, this Court
       determined that “the legislature intended an ordinary rebuttable presumption to apply, simply
       requiring the employer to offer some evidence that something other than [the] claimant’s
       occupation as a firefighter caused his condition.” (Emphasis omitted.) Id. ¶ 45. As such, in
       order to rebut the 6(f) presumption, it is not necessary that the employer eliminate any
       occupational exposure as a possible contributing cause of the claimant’s condition. Id. ¶ 51.
       Rather, once the employer introduces some evidence of another potential cause of the
       claimant’s condition, the presumption ceases to exist and the Commission is free to
       determine the factual question of whether the occupational exposure was a cause of the
       claimant’s condition based on the evidence before it but without the benefit of the
       presumption to the claimant. Id.
¶ 47       Here, as mentioned above, the Commission was aware of and specifically cited Thayer’s
       bursting bubble hypothesis in its decision. In determining the amount of evidence required to
       terminate the effect of the presumption, the Commission determined that “strong” evidence
       was required, a higher standard than “some evidence,” which this court found is required in
       Johnston. (Emphasis omitted.) Id. ¶ 45. The Commission found that the employer introduced
       some evidence to rebut the presumption through the testimony of Dr. Fintel. Dr. Fintel
       testified that the claimant had three major risk factors for heart disease: high cholesterol,
       hypertension, and obesity. He then testified that these “risk factors” caused the heart disease
       that resulted in a heart attack. We agree with the Commission that this constitutes sufficient
       evidence of another cause of the claimant’s heart disease and that the presumption thereby
       ceased to operate per our analysis in Johnston.2 Id. ¶ 51. As such, the Commission was free
       to determine the factual question of whether the occupational exposure was a cause of the
       claimant’s condition based on the evidence before it but without the benefit to the claimant of
       the presumption. Id. Accordingly, we find that the Commission properly applied the
       presumption set forth in section 6(f) of the Act. 820 ILCS 305/6(f) (West 2008).
¶ 48       Having found that the Commission properly applied the presumption set forth in section
       6(f) of the Act, we will proceed to determine whether the Commission’s determination that
       the claimant’s work as a firefighter did not cause his heart attack and underlying heart
       disease was against the manifest weight of the evidence. See Johnson, 2011 IL App (2d)

           2
            We note that hypertension, which is one of the major risk factors Dr. Fintel testified caused the
       claimant’s heart disease and resulting heart attack, is itself rebuttably presumed to be causally
       connected to the duties of a firefighter. 820 ILCS 305/6(f) (West 2008). However, evidence of the risk
       factors of high cholesterol and obesity remain as potential other causes, serving to “burst” the Thayer
       bubble and terminate the operation of the presumption. See Johnston, 2017 IL App (2d) 160010WC,
       ¶ 51.

                                                     - 12 -
       100418WC, ¶ 17. As previously stated, the Commission’s determination on a factual matter
       such as this is only against the manifest weight of the evidence if an opposite conclusion is
       clearly apparent. See Beelman Trucking, 233 Ill. 2d at 370.
¶ 49       Applying the appropriate standard of review to the Commission’s determination that the
       claimant’s employment as a firefighter for the City was not a cause of the claimant’s heart
       attack and underlying heart disease, we cannot say that an opposite conclusion is clearly
       apparent. The Commission was very specific in its decision as to its reasoning and its
       findings regarding the evidence. It found Dr. Fintel’s opinion to be more credible than that of
       Dr. Weaver because it found Dr. Fintel, as a cardiologist, is better credentialed and possessed
       a greater foundational understanding of the claimant’s condition. Dr. Fintel testified that the
       claimant’s risk factors—including his gender, obesity, age, poor diet, and high
       cholesterol—were the causes of the claimant’s condition. In reviewing the decision of the
       Commission, we give deference to its determinations resolving conflicts in the evidence or
       regarding credibility of witnesses and the weight that their testimony is to be given. Shafer v.
       Workers’ Compensation Comm’n, 2011 IL App (4th) 100505WC, ¶ 35 (citing Sisbro, Inc. v.
       Industrial Comm’n, 207 Ill. 2d 193, 206 (2003), and O’Dette v. Industrial Comm’n, 79 Ill. 2d
       249, 253 (1980)). For these reasons, we decline to disturb the Commission’s determination.

¶ 50                                       CONCLUSION
¶ 51       For the foregoing reasons, we grant the City’s motion to strike AFFI’s amicus brief as to
       any matters contained or referenced in AFFI’s brief that are de hors the record. We grant
       IML’s motion to file an amicus brief out of time. Further, we affirm the judgment of the
       circuit court, which confirmed the Commission’s decision.

¶ 52      Affirmed.

¶ 53       PRESIDING JUSTICE HOLDRIDGE, dissenting.
¶ 54       I join the majority’s judgment as to the amicus briefs and associated motions. However, I
       dissent from the remainder of the majority’s judgment for the reasons stated in my dissent in
       Johnston v. Illinois Workers’ Compensation Comm’n, 2017 IL App (2d) 160010WC,
       ¶¶ 65-72 (Holdridge, P.J., dissenting). Relying on Johnston, the majority holds that the City
       rebutted the presumption of causation prescribed in section 6(f) of the Act (820 ILCS
       305/6(f) (West 2014)) by presenting Dr. Fintel’s testimony that (1) the claimant had three
       major risk factors for heart disease (high cholesterol, hypertension, and obesity) and (2) these
       risk factors caused the claimant’s heart disease, which resulted in his heart attack. Supra ¶ 47.
       I disagree.
¶ 55       As I noted in my dissent in Johnston, in order to establish causation under the Act, a
       claimant need only prove that some act or phase of his employment was a causative factor in
       his ensuing injuries. Sisbro, Inc. v. Industrial Comm’n, 207 Ill. 2d 193, 205 (2003); Land &
       Lakes Co. v. Industrial Comm’n, 359 Ill. App. 3d 582, 592 (2005). Thus, the section 6(f)
       presumption of causation in this case required the factfinder to presume that the claimant’s
       employment as a firefighter was a contributing cause of his underlying heart disease, which
       caused his heart attack. In order to rebut this presumption, the City had to introduce evidence
       sufficient to support a contrary finding (i.e., a finding that the claimant’s employment was


                                                  - 13 -
       not a contributing cause of his heart disease).3 See Franciscan Sisters Health Care Corp. v.
       Dean, 95 Ill. 2d 452, 461-63 (1983). The City could do this by presenting expert testimony
       that (1) exposure to smoke or toxic fumes while fighting fires is not a risk factor for the
       claimant’s heart disease or (2) the claimant’s particular level of exposure to smoke or toxic
       fumes on the job did not causally contribute to his heart disease (i.e., it did not contribute to
       the development of such disease, aggravate or accelerate the disease, or aggravate or
       accelerate the claimant’s ensuing heart attack).
¶ 56       Here, the City did neither. Instead, it presented Dr. Fintel’s opinion that the claimant’s
       heart disease was caused by non-occupational risk factors. In rendering this opinion, Dr.
       Fintel did not address the claimant’s repeated exposure to smoke or toxic fumes during his 31
       years of employment as a firefighter. Nor did he explain why such exposure was not, or
       could not have been, a contributing cause of the claimant’s heart condition or ensuing heart
       attack. In fact, Dr. Fintel testified that he had no knowledge of the particular duties the
       claimant performed as a firefighter and no information regarding the claimant’s exposures to
       occupational risk factors while he was a firefighter. Thus, Dr. Fintel neither contradicted Dr.
       Weaver’s detailed account of the claimant’s occupational exposure to various toxic fumes
       nor rebutted Dr. Weaver’s opinion that the claimant’s employment may have been a cause of
       his cardiovascular disease and heart attack. Instead, Dr. Fintel merely pointed to other
       contributing causes that he opined were sufficient to cause the claimant’s cardiovascular
       disease and resulting heart attack. In sum, Dr. Fintel presented no facts or reasons supporting
       his conclusion that the claimant’s employment was not a contributing cause of his resulting
       illness. Nor did Dr. Fintel present any facts or reasons supporting a conclusion that the
       claimant’s employment did not aggravate or accelerate the claimant’s cardiovascular disease
       or ensuing heart attack. Accordingly, Dr. Fintel’s opinion lacked foundation (see Sunny Hill
       of Will County v. Illinois Workers’ Compensation Comm’n, 2014 IL App (3d) 130028WC,
       ¶ 36; Gross v. Illinois Workers’ Compensation Comm’n, 2011 IL App (4th) 100615WC, ¶ 24)
       and could not support a finding of no employment-related causation sufficient to rebut the
       section 6(f) presumption (see Franciscan Sisters Health Care Corp, 95 Ill. 2d at 462-63;
       Johnston, 2017 IL App (2d) 2160010WC, ¶ 70 (Holdridge, P.J., dissenting)).4

           3
              I disagree with the majority’s resort to legislative history in determining the quantum of evidence
       needed to rebut the presumption of causation prescribed by section 6(f). In my view, section 6(f) is
       unambiguous as to that issue; accordingly, it is unnecessary and inappropriate to consider legislative
       history in construing the statute. See Johnston, 2017 IL App (2d) 160010WC, ¶ 70 & n.4 (Holdridge,
       P.J., dissenting).
            4
              The City also presented the medical opinion of Dr. William Scott, which suffers from the same
       deficiencies as Dr. Fintel’s opinion. Dr. Scott opined that the claimant’s coronary artery disease was
       associated with personal risk factors, and he noted that “other men with similar personal risk factors in
       different occupations or even in no occupations can experience similar events.” However, Dr. Scott did
       not consider the claimant’s significant occupational exposure to smoke or toxic fumes or opine that
       such exposure could not have been a contributing, aggravating, or accelerating cause of the claimant’s
       coronary artery disease or heart attack. Instead, he merely opined that it would not be medically valid to
       assume that the claimant’s cardiac event “occurred solely due to his occupation as a firefighter,” while
       ignoring the claimant’s personal risk factors. (Emphasis added.) Supra ¶ 25. Accordingly, Dr. Scott’s
       opinion does not rebut the statutory presumption that the claimant’s employment with the City was a
       contributing cause of his cardiovascular disease or heart attack.

                                                      - 14 -
¶ 57       For the reasons set forth above, I would find that the City failed to rebut the statutory
       presumption of causation in this case. I would therefore reverse the Commission’s decision
       and remand the matter to the Commission.




                                                - 15 -
