The opinion of the court was delivered by: Justice McMORROW
This case involves three actions by three different plaintiffs, Lois Bicknell (Bicknell), Vernadine Thacker (Thacker), and Delores McClure (McClure), against defendant Owens Corning Fiberglas Corporation (Owens Corning). McClure also named Owens-Illinois, Inc. (Owens-Illinois), as a defendant in her suit. All three plaintiffs' complaints were based on injuries allegedly resulting from their husbands' exposure to asbestos while employed by the Union Asbestos and Rubber Company (Unarco) at its Bloomington, Illinois, plant. Neither Unarco nor Johns-Manville Corporation (Johns-Manville), a supplier of asbestos used in the Bloomington plant, is named as a defendant in plaintiffs' complaints. In addition, plaintiffs alleged no exposure to Owens Corning or Owens- Illinois products and no employment relationship between defendants and their husbands. Nevertheless, plaintiffs claimed that defendants were responsible for the injuries alleged in their complaints because defendants engaged in a civil conspiracy with Unarco, Johns-Manville, and other companies to suppress information concerning the harmful health effects of asbestos exposure and to falsely represent that it was safe for people to work in close proximity to asbestos-containing materials.
At plaintiffs' request, these three cases were consolidated for trial before the circuit court of McLean County. After trial, the jury returned verdicts in favor of Bicknell and Thacker against Owens Corning. The jury also found in favor of McClure against both Owens Corning and Owens-Illinois. The appellate court affirmed the judgments entered on these verdicts. 298 Ill. App. 3d 591. Owens-Illinois then filed a petition for leave to appeal the judgment in the McClure case, and Owens Corning filed a petition for leave to appeal the judgments in all three cases. This court granted defendants' petitions (177 Ill. 2d R. 315) and allowed plaintiffs' motion to consolidate defendants' appeals. In addition, we have permitted amicus curiae briefs to be filed by the Illinois Association of Defense Trial Counsel, the Product Liability Advisory Council, Inc., and the Illinois Manufacturers' Association. 155 Ill. 2d R. 345. We reverse on the basis that the evidence was insufficient to show that either defendant engaged in the alleged civil conspiracy with Unarco or Johns-Manville.
In her complaint against Owens Corning and Owens-Illinois, *fn1 Delores McClure, individually and as special administrator of the estate of Robert McClure, alleged that her husband, Robert McClure, worked in Unarco's Bloomington plant during the period 1959-61. She asserted that, while her husband worked at the Bloomington plant, he was exposed to asbestos, including asbestos that Johns-Manville supplied to Unarco. According to McClure, as a result of this exposure, her husband contracted asbestosis and lung cancer, which caused his death.
McClure asserted that defendants, Unarco, and Johns-Manville knew of the health hazards associated with asbestos exposure and had a duty to warn their employees of these hazards and to provide a safe workplace. She further alleged that defendants conspired with Unarco, Johns- Manville, and other companies to "positively assert in a manner not warranted by the information possessed by the conspirators, that *** it was safe for people to work with and in close proximity to asbestos and asbestos containing materials" and to "suppress information about the harmful effects of asbestos *** causing asbestos workers to be and to remain ignorant of that information." In furtherance of this alleged conspiracy, the conspirators, inter alia, sold asbestos without warning of its adverse health effects, refused to warn their own employees and Robert McClure about these hazards, and altered and suppressed published reports concerning these hazards. According to McClure, these acts were proximate causes of Robert McClure's injuries and death.
Lois Bicknell's complaint against Owens Corning (Owens-Illinois was a defendant only in McClure's complaint) *fn2 contained essentially the same conspiracy allegations stated by McClure. Bicknell alleged that, like Robert McClure, her husband, Hugh Bicknell, worked in Unarco's Bloomington plant, although his period of employment was 1954 to 1955. According to Bicknell, as a result of her husband's exposure to asbestos while working in the plant, he developed pulmonary fibrosis and lung cancer, which resulted in his death. Also like McClure, Bicknell alleged that her husband's injuries and death were proximately caused by the acts taken in furtherance of the alleged conspiracy.
Vernadine Thacker's complaint against Owens Corning *fn3 also contained the same allegations of conspiracy as McClure's complaint. Unlike McClure's and Bicknell's complaints, however, Thacker's complaint was based on her own exposure to asbestos. Thacker alleged that her husband, Charles Thacker, was employed at Unarco's Bloomington plant between 1952 and 1965. Thacker asserted that she was exposed to asbestos fibers carried home from the plant on her husband's person and clothing. According to Thacker, as a result of her exposure to these fibers, she developed pulmonary fibrosis and lung cancer. Thacker claimed that the acts taken in furtherance of the alleged conspiracy were a proximate cause of her injuries.
Prior to trial, the circuit court granted plaintiffs' motions to consolidate these three cases. It denied Owens-Illinois' motion requesting that it be tried separately from Owens Corning, although when evidence was admitted against only one of these parties during trial, the circuit court gave the jury a limiting instruction.
The trial was divided into two phases. All issues except for punitive damages were determined at the first phase. Defendants argue that the verdicts against them at the first phase must be overturned because there was insufficient evidence to support plaintiffs' conspiracy claims and because certain trial errors require reversal. We agree with defendants that the verdicts finding them liable for conspiracy cannot stand because the evidence does not permit a Conclusion that they agreed with Unarco or Johns-Manville to conceal the health hazards of asbestos from employees. The following is a description of the evidence relevant to our Disposition.
I. Medical and Scientific Literature
As circumstantial evidence of defendants' alleged knowledge of the health hazards of asbestos, plaintiffs presented evidence of the information about these hazards contained in medical and scientific publications during the relevant time periods. Prior to 1930, there were approximately 12 case reports linking asbestos and disease in Britain, the United States, and Europe. In 1930, the first epidemiological study relating asbestos exposure to disease was published. This study, which was published in Britain and the United States, showed that approximately 25% of the asbestos industry workers studied had lung scarring and that the scarring was more severe in individuals who worked in dustier areas and had been exposed to asbestos for longer amounts of time. To prevent such lung damage, the author recommended dust control, respiratory protection, periodic health examinations of the workers, and education of workers concerning the risks of asbestos.
In 1938, a bulletin issued by the United States Public Health Service reported the results of a study on asbestos textile manufacturing employees. The study connected asbestosis, which is irreversible lung scarring caused by asbestos fibers, to exposure to asbestos dust in concentrations greater than five million particles per cubic foot. The bulletin contained a recommendation that dust levels be kept below this threshold in order to prevent asbestosis.
In the 1940s and 1950s, the five million particles per cubic foot threshold limit value for asbestos was adopted by the American Conference of Governmental and Industrial Hygienists and by many states, including Ohio and New Jersey. In the 1950s, however, the five million particles per cubic foot asbestos dust limit was criticized in the medical and scientific literature because it was designed only to prevent asbestosis and did not account for the cancer risk associated with asbestos exposure. Nevertheless, the threshold limit value for asbestos remained the same until 1969, when it was lowered.
Beginning in the 1930s, case reports linking asbestos to lung cancer were published in the medical and scientific literature. In 1955, an epidemiological study involving asbestos and lung cancer was published in the British Journal of Industrial Medicine. This study found that asbestos manufacturing workers with asbestosis had 10 times the rate of lung cancer as the general population. In 1960, an epidemiological study linking asbestos exposure to mesothelioma, a cancer of the membrane surrounding the lungs, was published in the British Journal of Industrial Medicine.
In the 1960s, Dr. Irving Selikoff began a large scale epidemiological study of asbestos and disease. Selikoff became one of the leading authorities on asbestos and disease. Throughout the 1960s , 1970s, and 1980s, Selikoff published the results of an ongoing health survey of members of the International Association of Heat and Frost Insulators and Asbestos Workers Union. In a 1964 article published in the Journal of the American Medical Association, Selikoff stated that, although many researchers had questioned the link between lung cancer and asbestosis, the results of his study proved that there was a connection. He found that asbestos exposure put insulation workers at greater risk for diseases such as asbestosis, lung cancer, and mesothelioma. These diseases were most apparent in workers with more than 20 years since the date of their first exposure.
II. Efforts by Asbestos Product Manufacturers Other Than Owens Corning and Owens-Illinois to Suppress Information Concerning the Health Hazards of Asbestos
As other circumstantial evidence of defendants' involvement in the alleged conspiracy, plaintiffs presented evidence intended to demonstrate that defendants' actions paralleled those of the other alleged conspirators. Plaintiffs' theory at trial was that parallel conduct by the alleged conspirators demonstrated an agreement among them to suppress and misrepresent the health hazards of asbestos. The majority of the evidence at trial related to similarities and differences in the activities of the alleged conspirators.
For example, plaintiffs presented evidence that, at the same time that information about the health hazards associated with asbestos exposure was appearing in medical and scientific publications, asbestos product manufacturers other than defendants were causing published reports of such information to be suppressed or altered. There was no evidence that defendants participated in these particular activities. Instead, evidence of the actions of these other companies was part of plaintiffs' evidence of alleged parallel conduct.
There was evidence that attorneys for Johns-Manville and Raybestos- Manhattan, another asbestos product manufacturer, edited an article published in 1935 by Dr. Anthony Lanza, a physician employed by Metropolitan Life Insurance Company. Prior to publishing this article, which discussed the results of a study of workers at plants where asbestos-containing products were manufactured, Lanza permitted these attorneys to review the article and incorporated the changes they suggested. These were changes that were favorable to the asbestos- containing products industry or consistent with its legal positions. According to plaintiffs' expert, Dr. Barry Castleman, the substance of these changes was inconsistent with information contained in medical and governmental literature at the time.
Plaintiffs also presented evidence that, around the same time, Raybestos-Manhattan and Johns-Manville prevented the publication of information concerning the health hazards of asbestos in Asbestos magazine, a monthly trade publication. In September 1935, the editor of Asbestos magazine wrote Sumner Simpson, the president of Raybestos- Manhattan, to ask whether Simpson had any objections to the magazine publishing information about asbestosis and efforts to control it. The editor observed: "Always you have requested that for certain obvious reasons we publish nothing, and, naturally your wishes have been respected." Simpson consulted with Vandiver Brown, an attorney for Johns-Manville, about the editor's request, and the two men agreed that it would be better if nothing were said about asbestosis.
C. Results of the Saranac Laboratory Research
Similarly, plaintiffs presented evidence that, due to the actions of certain asbestos product manufacturers other than defendants, information concerning the health hazards of asbestos exposure was omitted from a 1951 article discussing the results of a study conducted by the Saranac Laboratory. In 1936, a group of asbestos product manufacturers agreed to sponsor research on the health effects of asbestos dust. Members of this group included Johns-Manville and Unarco but not defendants. In their agreement with Saranac, the sponsoring companies required that the results of the research remain their property, that they maintain control over the disclosure of the results, and that any manuscript discussing the results be submitted to them for approval prior to publication.
Consistent with this agreement, Saranac submitted a manuscript to the sponsoring companies. At a meeting, these companies agreed that certain changes should be made to the manuscript, and Saranac incorporated these changes. For example, at the request of the sponsoring companies, references to cancer and tumors were removed from the manuscript before publication. The published article nevertheless stated that it is a "complete survey" of the research and did not acknowledge the input of the sponsoring companies.
III. Unarco's and Johns-Manville's Plant Operations
Additional evidence relating to plaintiffs' parallel-conduct theory included testimony that Unarco and Johns-Manville failed to warn their employees of the health hazards of asbestos exposure and failed to protect their employees from these hazards. Employees who worked in Unarco's Bloomington plant during the fifties and sixties testified that Unarco never told them or other employees that breathing asbestos dust posed any health risks. These employees also described conditions in the Bloomington plant before Owens Corning purchased it from Unarco in 1970. According to these employees, the plant used raw asbestos supplied by Johns-Manville to make insulation and other products. Dust from the plant operations was released into the air of the plant. The dust in the air was visible and covered surfaces in the plant. Ron Thacker, plaintiff Vernadine Thacker's son, testified that he worked with his father in the plant and, when they left the plant, there was dust on their clothing and hair.
These employees further testified that Bloomington plant employees were not required to wear respirators. One employee stated that he had a respirator, but employees did not use them frequently because they had difficulty obtaining filters for the respirators, and the filters needed to be changed every day. There was some dust-collection equipment in the plant, but it did not collect all of the dust because there was always dust in the air. Unarco had no ventilation equipment and no industrial hygienist. Unarco also did not require employees to get annual chest X rays. According to the industrial hygiene survey Owens Corning conducted during the summer after it purchased the Unarco plant, atmospheric conditions in the Bloomington plant were "unbelievably bad," and exposures to asbestos were "excessive."
A Johns-Manville employee testified that, during the period 1946 to 1961, Johns-Manville did not give its employees warnings about the health hazards of asbestos. Johns-Manville did require employees to undergo periodic physical examinations, which included a chest X ray. These X rays were read, however, by Johns-Manville's own doctors and treated as the property of the company. It was Johns-Manville's policy not to inform an employee that his X ray showed asbestosis or another lung disease unless the disease became disabling. This policy did not change until the early 1970s.
IV. Evidence of Owens-Illinois' Activities
In an attempt to connect Owens-Illinois and Owens Corning to Unarco and Johns-Manville, plaintiffs presented evidence intended to show that defendants' actions with respect to their own production and distribution of asbestos-containing products were similar to Unarco's and Johns-Manville's. The evidence relating to defendants focused on their manufacture of "Kaylo," a high-temperature hydrous calcium silicate insulation.
In 1948, Owens-Illinois began commercial production and distribution of Kaylo. Kaylo included 15% to 22% asbestos. In 1953, Owens-Illinois and Owens Corning entered into an agreement under which Owens-Illinois continued to manufacture Kaylo, but Owens Corning assumed the responsibility for distribution. In 1958, Owens-Illinois sold the Kaylo division to Owens Corning. Owens Corning also purchased plants where Owens-Illinois had manufactured Kaylo, including its plant in Berlin, New Jersey. Although Owens Corning manufactured other asbestos- containing products, Kaylo was the only asbestos-containing product manufactured by Owens-Illinois. Beginning in the late sixties, Owens Corning performed research to find a substitute for the asbestos in Kaylo. A substitute was found in 1972, after which Owens Corning also did not manufacture asbestos-containing Kaylo.
A. Knowledge and Communication of Health Hazards
With respect to Owens-Illinois' knowledge of the health hazards associated with exposure to Kaylo, there was evidence that, in 1943, Owens-Illinois hired Saranac Laboratory to determine whether Kaylo presented an air hazard when mixed, sawed, or applied. In its initial correspondence with Owens-Illinois, Saranac expressed the desire to publish any results of this research, but stated that "nothing [would] be published without [Owens-Illinois'] authorization."
In 1946, Saranac reported to Owens-Illinois that, with respect to the Kaylo experiments, "no serious results [had] developed ***. The dust alone [was] not causing anything suggestive of either silicosis or asbestosis." According to the preliminary report Saranac provided in 1947, Kaylo dust was biologically inactive, did not cause silicosis or asbestosis, and would probably be harmless if inhaled in moderate amounts by humans over a long period of time. Just one year later, however, in November 1948, Saranac informed Owens-Illinois that further research had revealed that Kaylo dust did in fact cause asbestosis. Saranac reported: "Kaylo *** is capable of producing asbestosis and should be handled as a hazardous industrial dust."
Saranac submitted the final report on the Kaylo research to Owens- Illinois in February 1952. According to this final report, Kaylo was capable of causing a "peribronchiolar fibrosis typical of asbestosis," as a result of which, "every precaution should be taken to protect workers against inhaling the dust." Saranac indicated that it hoped to publish the results of the Kaylo research but that it would omit references to Kaylo and Owens-Illinois from any publication to protect the interests of the company. In addition, Saranac told Owens-Illinois that it would submit a manuscript to Owens-Illinois prior to publication and would welcome comments by Owens-Illinois.
Subsequent correspondence, however, indicates that, because of management changes at Saranac, Owens-Illinois was never given the opportunity to review the article discussing the results of the Saranac research before this article was published. The article contained no references to Kaylo or Owens-Illinois.
In an effort to show that Owens-Illinois failed to share the information it had about the health hazards of Kaylo with its employees or consumers, plaintiffs presented evidence that Owens-Illinois failed to place warning labels on Kaylo during the time it manufactured this product. Plaintiffs also showed that, in 1952, Owens-Illinois issued an advertising brochure in which it represented that Kaylo was nontoxic. There was conflicting evidence at trial as to the meaning of "toxic" and the applicability of this term to asbestos.
In addition, plaintiffs presented the testimony of Jerry Helser, who had worked for Owens Corning since 1961. Helser testified that, during the first few years of his employment at Owens Corning, he worked with individuals who had previously worked for Owens-Illinois at its Berlin plant and other locations. According to Helser, none of these former Owens-Illinois employees told him that the asbestos used in Kaylo caused lung scarring and cancer or gave him any indication that Owens-Illinois had informed them of these risks.
Contrary to Helser's testimony, a former Owens-Illinois employee, Richard Grimmie, testified that Owens-Illinois employees at the Berlin plant did receive warnings about the health hazards associated with exposure to the asbestos in Kaylo dust. Grimmie testified that he began working for Owens-Illinois in 1945. Grimmie stated that, before beginning work at the Berlin plant, he received a physical examination. At the time of this examination, he was told about asbestos and asbestosis and was informed that respirators were required in certain areas of the plant because of the silica and asbestos content of Kaylo.
Grimmie testified that he informed job applicants about the hazards of asbestos when he worked as personnel manager for Owens-Illinois. He testified that he told applicants that respirators were required in certain areas of the plant and that the plant manufactured a product containing silica, which causes silicosis, and asbestos, which causes asbestosis.
In addition to evidence of Owens-Illinois' communications concerning the health hazards of exposure to Kaylo dust, there was evidence relating to the conditions of the plants where Kaylo was manufactured. Grimmie testified that the Berlin plant employed a very large, powerful, and well-maintained dust collector with inlets near certain dusty plant operations, such as the saws used to shape the finished Kaylo product. In addition to the dust collector, Owens-Illinois had mechanical sweepers to vacuum dust from the floors and, before the end of each shift, workers were given time to clean their work areas.
According to Grimmie, Owens-Illinois also had a respirator program, under which employees were required to wear respirators in areas where dust could not be controlled. The plant nurse administered the program. Respirators with clean filters were given to workers by their supervisors at the beginning of each shift. At the end of the shift, the respirators were returned to the nurse, who would clean the filters. Workers often refused to wear their respirators and were disciplined for these refusals. Grimmie testified that Owens-Illinois also employed an industrial hygienist, Willis Hazard, who would frequently take dust samples throughout the plants.
Grimmie further testified that Owens-Illinois required every Owens- Illinois employee at the Berlin plant to have a preemployment X ray and annual X rays thereafter. Grimmie was aware of no asbestos-related disease showing on any employee's X ray during the time Owens-Illinois owned the Berlin plant. Grimmie was also unaware of any asbestos-related workers' compensation claim made during this time.
In addition to Grimmie's testimony, there was evidence of an industrial hygiene survey taken at the Berlin plant a few days before and a few days after ownership of the Berlin plant was transferred from Owens-Illinois to Owens Corning in 1958. Consistent with Grimmie's testimony, the report noted that employees working at certain operations were wearing respirators and that exhaust systems were available at certain locations. Nevertheless, the report stated that several air samples exceeded or closely approached acceptable limits for asbestos dust. One sample taken near a saw ...