Formaldehyde is an economically important chemical that is used in numerous different materials. Thousands of employees are exposed to it each year by means of breathing it in or coming into contact with liquid formaldehyde. Formaldehyde is also exposed to people out in the environment because it is a byproduct of vehicle engines and cigarette smoke. Formaldehyde causes irritation to the lungs, eyes and throat and is also a known carcinogen. This study proposal seeks to determine whether there is an association between lung cancer and formaldehyde exposure. This study would be conducted as a prospective cohort study following around 400 employees in the industrial surfactant industry. Half of the employees are a control and half of them that have formaldehyde exposure. Data would be gathered by means of industrial hygiene air sampling and interviewing of employees and management about exposure and their job tasks and duties. The predicted outcome is that there is an association between formaldehyde exposure and lung cancer.
There are many different types of industries that have exposure to formaldehyde that is breathed into the lungs by employees every day. There is a wide range of industrial settings as well as other areas that expose employees to formaldehyde. Symptoms of exposure to formaldehyde range from a burning sensation in the eyes and throat, difficulty breathing and cancer (1). Formaldehyde is classified as a known human carcinogen (2).
Formaldehyde is a colorless, strong smelling gas that is an economically important chemical with approximately 46 billion pounds produced worldwide each year. This is in the form of an aqueous solution. With this much being produced in the industry each year, this means that there are a lot of employees that are involved in the production and are possibly exposed to formaldehyde. Formaldehyde is used in the manufacturing of industrial surfactants as a preservative.
Routes of exposure to formaldehyde occur through breathing gas or vapor into the lungs and can also be absorbed through the skin. Formaldehyde comes from many different sources such as manufacturing of building materials, household materials, resins, molding compounds, automobile engines, embalming and tobacco smoke (1, 3, 4). In the manufacturing facilities, exposure may come from leaking or open equipment and the treatment of textiles and the production of resins. This leaves the employee exposed to the gas or vapor. This is an issue because more time is spent by employees inside at most workplaces than outside and more sources of chemical irritants are indoors leading to a greater concentration than is seen outdoors (5). A greater amount of exposure may occur for certain employees that are exposed more than others due to being in the area more often/frequently than others. The permissible exposure limit for formaldehyde is 0.75ppm (6).
Studies have shown that exposure to formaldehyde is associated with respiratory symptoms, and eye, nose and throat irritation. Repeated contact with the liquid has also resulted in allergic contact dermatitis in humans (4). Since formaldehyde is associated with respiratory symptoms and is involved in nasopharyngeal cancer there is the question of whether formaldehyde also causes lung cancer.
When an employee is exposed to formaldehyde, the effects are shown not too long after the job begins. The effects can vary greatly as from the cases of exposure previously stated; between starting work and the first development of symptoms was 4 years. Some employees may improve over a weekend or it may take a week of work to see improvements. The effects of long term exposure to respiratory irritants have been shown to cause, aggravate, or even induce asthma symptoms in individuals that were previously healthy (7). About 15% of adult onset asthma is caused by exposure to a respiratory sensitizer or irritant. Most of these cases go undiagnosed and pose a significant cost to the public (8).
Formaldehyde is a chemical that is regulated by OSHA that has a PEL of 0.75ppm. There are many employees that are exposed to it each year through their workplace and the environment. This study seeks to determine if there is an association between formaldehyde exposure and lung cancer.
Hypothesis and Methods
An alternate hypothesis is that formaldehyde is associated with lung cancer in those employees that are exposed to formaldehyde in the industrial surfactant industry. The null hypothesis is that formaldehyde is not associated with lung cancer in those employees that are exposed to formaldehyde in the industrial surfactant industry. Current research has shown that formaldehyde is a known human carcinogen associated with nasopharyngeal cancer (3). This hypothesis would be tested using a prospective cohort study. The study will look at those that work in the area where formaldehyde is used in the workplace. The exposure occurs through breathing formaldehyde that is in the air. Looking into this area would help to determine if formaldehyde is a contributing factor to lung cancer as many people are exposed to formaldehyde in the occupational setting and not just in the industrial surfactant industry as this is the only industry this study would look at.
The data would be gathered by following approximately 200 people in the industrial surfactant industry at a single facility. There would be another 200 people in the study that work in the industry for a control, but aren’t exposed to formaldehyde. The study would be looking into the amount of time the person was employed in the industry at the facility, the frequency of formaldehyde exposure, the average level of formaldehyde that the person was exposed to and the peak exposures. This study would follow them around for 10 years. Calculating relative risk would be used to compare the mortality rates of those with lung cancer with those of the general population. These rates would be looked at and compared with age, race/ethnicity and sex. A dose-response association would be determined to see what had statistical significance. This could be hold long they were employed, the frequency of exposure, the average amount formaldehyde they were exposed to or the amount of peak exposures. The peak exposure would be defined as exceeding the PEL (Permissible Exposure Limit) for a period of less than 15 minutes.
Industrial hygienists would perform air sampling at the facility every year or so to determine levels at which employees are exposed, the frequency of the exposure and the peaks of exposure. They would also have discussions with the plant workers and management. These discussions would include how often certain high exposure tasks are performed, what the routine and non-routine tasks are and the kinds of process upsets that might happen or that do happen at the facility. The industrial hygienists would look into what other exposures to workers there are at the facility that might affect the results. These confounding variables could be air pollutants such as asbestos and if the person smokes cigarettes or is exposed to secondhand smoke at home. This would be controlling by choosing people that don’t smoke aren’t exposed at home and aren’t involved in asbestos abatement.
Limitations of this study are that studies on formaldehyde exposure that have an association with lung cancer have not been conducted. This study was also be subject to what the worker and management had told the industrial hygienists. There could be a variance in what they remembered in how often a task was performed and how much it happened in reality and the amount of exposure. This is also a small sample size compared to other ecologic studies done on the association between formaldehyde exposure and nasopharyngeal cancer. This study looks at formaldehyde exposure over a period of 10 years and it may take longer for lung cancer to develop as a result of formaldehyde exposure.
Predicted outcomes are that the results show that there is an association between exposure to formaldehyde and lung cancer. The data would show that those that worked in the industrial surfactant industry for a longer period of time, those that were more frequently exposed to formaldehyde, those that had a higher level of average exposure to formaldehyde and the amount of peak exposures will have a higher occurrence of lung cancer. The control group will have a relative risk that is the same as the general population in regards to lung cancer. The null hypothesis would therefore be rejected because there would be an association found between formaldehyde exposure and lung cancer. More research would need to be conducted in this area in other industries such as embalming, primary metals, materials manufacturing (i.e. carpet, building materials) and chemical manufacturing.
- An Introduction to Indoor Air Quality (IAQ): Formaldehyde. (2012, June 20). EPA: United States Environmental Protection Agency. Retrieved April 25, 2014, from http://www.epa.gov/iaq/formaldehyde.html
- Formaldehyde and Cancer Risk. (2011, June 10). National Cancer Institute at the National Institutes of Health. Retrieved April 25, 2014, from http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde
- Hauptmann, M., Lubin, J., Stewart, P., Hayes, R., & Blair, A. (2004). Mortality from Solid Cancers among Workers in Formaldehyde Industries. American Journal of Epidemiology, 159, 1117-1130.
- Zhang, L., Steinmaus, C., Eastmond, D., Xin, X., & Smith, M. (2009). Formaldehyde exposure and leukemia: A new meta-analysis and potential mechanisms. Mutation Research/Review in Mutation Research, 681, 150-168.
- Tageldin, M., Raafat, H., Elassal, G., & Salah Eldin, W. (2014). Influence of indoor respiratory irritants on the course of bronchial asthma. Egyptian Journal of Chest Diseases and Tuberculosis, 63, 291-298.
- OSHA Fact Sheet: Formaldehyde. (2011, April 1). United States Department of Labor: OSHA. Retrieved April 25, 2014, from https://www.osha.gov/OshDoc/data_General_Facts/formaldehyde-factsheet.pdf
- Brooks, S. (2010). Occupational, Environmental, and Irritant-Induced Cough. Otolaryngol Clin N Am, 43, 85-96.
- Baur, X., Sigsgaard, T., Aasen, T., Burge, P., Heederik, D., Henneberger, P., et al. (2011). Guidelines for the management of work-related asthma. European Respiratory Journal,39, 529-545.