In 2010, Plaintiff Tanu Vatuvei, a 33-year-old food-flavoring factory worker, was diagnosed with bronchiolitis obliterans, a disease which causes severe and irreversible scarring of the airways. It was believed his disease resulted from workplace exposure to diacetyl, a naturally occurring chemical used for butter-flavoring of food, while working at Mission Flavors & Fragrances Inc., in Foothill Ranch, Orange County. Vatuvei sued Mission Flavors and several companies that supplied it with diacetyl during his employment, from 2000 to 2010. All the defendants settled out of the case prior to trial, except for supplier Citrus & Allied Essences Ltd., which stopped selling diacetyl in 2005. Counsel for Vatuvei alleged that he was exposed to diacetyl at Mission; that this exposure caused his lung damage; and that Citrus failed to provide adequate or timely warnings of the known dangers of inhaling diacetyl vapors. It was also claimed that Mission had knowingly placed him in an unsafe work environment, but that claim was dropped when the Vatuvei settled with Mission, before trial. Mission had been investigated and fined by the California Division of Occupational Safety and Health (“Cal/OSHA”), but this information was barred from the jury. In 2004, Cal/OSHA began investigating Mission after a co-worker of Vatuvei’s was diagnosed with bronchiolitis obliterans. Mission was fined for several serious violations and afterward hired a team of specialists from the National Jewish Medical Center (“NJMC”) in Denver, to provide assistance in rendering Mission a safe place to work. NJMC provided assistance with industrial hygiene, recommending installation of local ventilation controls and improved respiratory protection equipment. Mission was placed on a medical surveillance program, which required all employees, including Vatuvei, to undergo regular lung exams to determine whether the workers had sustained, or were sustaining, lung damage. Workers were also fitted for, and trained in, the use of respirators, and were provided with other necessary safety training, all of which previously had not been done. Plaintiff contended that Mission was aware that Vatuvei’s medical examination showed abnormal lung function, but that supervisors continued to tell him that the chemicals were safe. Between 2005 and 2007, Vatuvei was seen regularly by physicians from NJMC as part of the medical monitoring program. In 2007, he was sent by Mission to be treated by a NJMC pulmonologist, who initially determined that he did not have bronchiolitis obliterans, and instead, was suffering from asthma and/or chronic obstructive pulmonary disease (COPD), as effects of a more than 20-year smoking history. However, Vatuvei’s condition continued to deteriorate, and in 2010, he was re-evaluated and diagnosed with bronchiolitis obliterans. Citrus contended that Vatuvei did not have bronchiolitis obliterans, and that the initial diagnosis by NJMC of asthma and COPD was correct. Citrus also argued that it had previously warned about the necessary precautions to be taken when using the chemical. Citrus further challenged Vatuvei’s assertion that a better warning would have prompted Mission to improve the safety measures taken when working with diacetyl and other such chemicals. Citrus stated that Mission had demonstrated its disregard for its workers’ respiratory health, and better warnings would not have caused Mission to change its practices. The company further noted that Mission had built and helped design the building in which it was operating since 2001, yet had failed to include any ventilation or other respiratory controls in the plans.Mission had not included air conditioning for the workers on the floor, though it was provided for the management offices and the lab area. Ventilation on the work-floor consisted of propping a floor fan in a doorway open to the outside to bring in fresh air, Citrus asserted. Citrus also argued that plaintiff’s claims were time-barred, as he had been informed by the NJMC doctors in 2005 that his lung-test results were abnormal, triggering the running of the statute of limitations., Since Vatuvei was diagnosed in 2010 with Bronchiolitis Obliterans, he has lost approximately 60 percent of his lung capacity, allegedly due to his exposure to diacetyl. He sought recovery for claims including lost wages for the remainder of his work life, arguing that he was permanently disabled. Bronchiolitis obliterans is often referred to as “Popcorn Lung,” because it has affected several food-flavoring factory workers, some of the first of whom were in factories making microwave popcorn and/or its flavoring. The condition is characterized by the scarring or “obliteration” of the small airways or bronchioles, which leads to diminished lung capacity and breathing problems similar to asthma. However, unlike asthma, bronchiolitis obliterans is non-responsive to bronchodilators (such as Advair or Spiriva). Significant response to bronchodilators by the patient can be reason alone to rule out bronchiolitis obliterans as a diagnosis, and Vatuvei’s medical records showed several instances of significant response to bronchodilators. The disease is irreversible and, in severe cases, can require a lung transplant. It can also lead to death. Diacetyl is a naturally occurring substance, found in butter, beer, coffee, and other foods. It can be manufactured synthetically, but is chemically identical to natural diacetyl. It has been designated GRAS (Generally Regarded As Safe) for consumption, and has been safely used as a flavor additive for decades. However, studies have shown that it can cause lung damage when used without adequate ventilation and/or appropriate respiratory protection. Early in the 2000s, health officials found a link between bronchiolitis obliterans and exposure to flavoring chemicals used to make butter flavoring, which include diacetyl, Acetoin, and dozens of others. Diacetyl is one of the most prevalently used butter flavoring chemicals, and is usually used in the highest quantities. As a result, it is considered at least a marker for a situation presenting a risk of lung disease, and is generally considered as contributing to the development of bronchiolitis obliterans. It is still unknown whether other chemicals also present a similar risk, and what role each such chemical might have in the development of lung disease, either by itself or in combination with other such chemicals. Citrus also challenged Vatuvei’s claimed damages. While Vatuvei’s counsel argued for damages based on a possible lung transplant, his own treating pulmonologist testified that he did not need a transplant, as his condition was not so severe as to warrant it. Specifically, the company claimed, one needs to have less than 20 percent lung capacity and have less than two years to live before a transplant is considered. Further, Vatuvei’s treating physician and expert in pulmonology testified that he would not be eligible because of his morbid obesity.