A number of studies have been performed in various factory settings, and the findings of many of the studies have been concerning. One of the studies examined workers at a gun factory who were exposed to solvents such as toluene, acetone, butanol, xylene, benzene and trichloroethylene. Some of these solvents are found in tobacco smoke, and the authors of the study discovered that asthma-related symptoms were more common in the group of workers exposed to these chemicals than in workers who were unexposed. Another study found that workers at a cement factory were at high risk of developing chronic respiratory conditions such as COPD, due to their constant exposure to dust. Similarly, saw mill factory workers were found to be at high risk of respiratory disease due to their high levels of exposure to saw dust.
In August 2000, it was noted that a few former employees of a microwave popcorn plant in Jasper, Mo., had been diagnosed with a condition called bronchiolitis obliterans. This is a very serious lung condition that is irreversible and can be fatal. The smallest airways in the lung, known as the bronchioles, become scarred and constricted and block air movement. After an investigation by the National Institute for Occupational Safety and Health (NIOSH), it was found that some flavorings can cause lung disease when inhaled. Diacetyl is a chemical used to create the butter flavor in many foods, including popcorn, and it's believed to be responsible for bronchiolitis obliterans in the popcorn factory workers. For this reason, the condition is also known as popcorn lung. It's believed that flavoring chemicals can cause other respiratory issues, including new-onset asthma or asthma exacerbations in those with pre-existing asthma. In general, factory workers need to wear protective safety gear and are encouraged to seek prompt medical attention should any respiratory issues arise.