What is Vinyl Chloride Toxicity?
Vinyl chloride monomer (VCM) is a colorless gas with a sweet smell. It’s mainly used to make polyvinyl chloride (PVC), a material often found in building supplies, construction, and household furniture. Before the 1970s, it was also used as a propellant for aerosol cans and as a refrigerant. But, it’s now known to be a type of substance that can cause cancer, known as a carcinogen. This classification comes from a well-respected cancer research agency, the International Agency for Research on Cancer.
In 1974, the link between VCM and cancer became clear when three workers at a VCM production plant developed a very rare kind of liver cancer called hepatic angiosarcoma. This prompted an extensive investigation which confirmed that VCM was indeed the cause of the cancers. As a result, the Occupational Safety and Health Administration, a US agency responsible for health and safety in the workplace, lowered the allowed amount of VCM that workers could be exposed to from 500 parts per million to 1 part per million. They also required industries to modify their practices to comply with these new rules. Since this safer standard was established in 1975, it’s believed that no cases of this rare liver cancer have developed in workers exclusively exposed to VCM after the new rules were established.
What Causes Vinyl Chloride Toxicity?
Vinyl chloride toxicity typically happens when a person is exposed to this chemical at work, especially during the process of turning vinyl chloride monomer (VCM) into polyvinyl chloride (PVC – a common type of plastic). There have also been instances where people were exposed to it because of industrial accidents or spills.
There were cases in the 1960s and early 1970s, where people were exposed to significant amounts of vinyl chloride as it was used in aerosol sprays. But, it’s no longer used this way. In developed countries, it’s now rare for people to be exposed to high levels of this chemical at work. But, in developing countries, there are still cases where workers have been exposed to it over the past 10 to 20 years. Such exposure can lead to a rare type of liver cancer, called hepatic angiosarcoma (HAS).
Apart from being used in the industry, tiny amounts of vinyl chloride are found in cigarettes. Also, if PVC waste in the environment is broken down by bacteria, it could release vinyl chloride. It’s even possible to find low levels of this chemical in groundwater near waste sites. However, no cases of liver cancer like HAS have been linked to such low-level exposures.
The Agency for Toxic Substances and Disease Registry’s (ATSDR) profile on vinyl chloride in 2006 stated that vinyl chloride is a volatile compound. It means that it easily turns into a gas when it’s in the environment. So, it doesn’t really build up in places like groundwater.
Risk Factors and Frequency for Vinyl Chloride Toxicity
The US Environmental Protection Agency (EPA) reports that every year, 10 to 20 billion pounds of vinyl chloride are produced at between 15 to 20 sites, many of which are near Baton Rouge, Louisiana. From 1974 to 2000, there were 197 reported cases of vinyl chloride-related health issues among workers worldwide, often appearing around 20 years after exposure. The highest number of cases were reported in the mid to late 1970s, among workers cleaning reactor vessels who were likely exposed to high levels of vinyl chloride, up to 3000 parts per million.
Signs and Symptoms of Vinyl Chloride Toxicity
The information about a person’s exposure to harmful substances at their workplace or in their environment is crucial for treatment. But remember, addressing any immediate, life-threatening condition should be the priority. In cases of sudden exposure, symptoms can vary based on the degree of exposure. Mild symptoms might include dizziness, breathlessness, and headaches, while severe exposure might cause depression, respiratory failure, and in extreme cases, death.
People who have been significantly exposed to Vinyl Chloride Monomer (VCM – a harmful substance) in the past or are continually exposed to it may exhibit the same mild symptoms. Alongside these symptoms, there could be general discomfort, night sweats and weight loss, especially if there is a presence of malignancy. However, individuals with liver abnormalities due to VCM may not show typical signs of liver failure.
During a physical examination, signs of problems caused by VCM might be seen. In cases of acute exposure, trouble breathing or extreme sleepiness might be an early warning sign. Long-term exposure can result in complications such as thickening of the skin over the hands and fingers, Reynaud’s phenomenon (change in color and feeling in the fingers and toes due to cold or stress), and acroosteolysis (bone resorption) among others. In severe cases, patients with advanced liver abnormalities may have swollen abdomen, fluid in the abdominal cavity or severe weight loss.
Testing for Vinyl Chloride Toxicity
People who work in the process of creating PVC from VCM should regularly have tests to check their exposure level. According to a standard set by the Occupational Safety and Health Administration (OSHA), which is standard 1910.1017, workers exposed to more than the allowed level of 0.5 ppm of VCM should have a work-related health checkup every year.
This health checkup includes lab tests that keep an eye on particular indicators in the body, such as total bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine transaminase, and gamma-glutamyltransferase. These should be monitored at least once a year. However, ordinary measures of liver function might not show any abnormal signs until the late stages of HAS, so other indicators might be a better choice.
While a liver biopsy can give the most accurate results for the specific damage caused by vinyl chloride, this test is fairly invasive and carries some risks, which makes it less ideal for regular checks.
Treatment Options for Vinyl Chloride Toxicity
If you’re facing exposure to Vinyl Chloride Monomer (VCM), a potentially harmful chemical, the first goal should be to avoid contact with it. Your employer and workplace should be taking precautions to prevent this type of exposure.
If you are suspected or confirmed to have been exposed to VCM, it’s crucial to immediately stop further exposure. This is done by moving away from the contaminated area and cleaning any external contact from your body. Quick action is vital, making sure to move to open air and away from areas with bad ventilation. VCM gas is heavier than air, so it can gather in low spots. If you’re part of a rescue team dealing with an industrial accident or train derailment, you might need specific protective clothing and independent breathing equipment to stay safe.
People who have experienced severe reactions, like difficulty breathing and low consciousness, might need critical care for a while. VCM is a type of chemical that can make your heart more sensitive to stress hormones, causing dangerous irregular heartbeats. So if the exposure is serious, your heart activity should be monitored, and the use of medications that stimulate the heart should be limited.
If workers show signs of liver problems or ongoing illness, they should see a specialist for further tests. An occupational medicine doctor or toxicologist can assess if the symptoms are due to exposure to VCM, and a liver specialist can look into potential liver damage and possible health problems due to VCM exposure.
What else can Vinyl Chloride Toxicity be?
If you are exposed to vinyl chloride monomer (VCM), a type of industrial chemical, you might experience symptoms ranging from mild to severe. These could include shortness of breath, cough, dizziness, headaches, trouble breathing, and even issues with your central nervous system. However, these symptoms could also be caused by a number of other industrial toxins, particularly chemicals called volatile halogenated hydrocarbons. Knowing if you’ve been exposed to VCM can help doctors pinpoint the cause of your symptoms.
On the other hand, if you’ve been exposed to VCM over a long period of time at work, you could experience other symptoms. These might include Raynaud’s phenomenon (a condition that affects your fingers and toes), thickening of the skin on your hands and forearms, and shortening of your fingers. These symptoms can look a lot like a disease called systemic sclerosis. But doctors can tell the difference because if you have systemic sclerosis, your body would produce certain substances called antinuclear antibodies. Plus, if you’ve been exposed to VCM, that could explain your symptoms. Raynaud’s phenomenon could also be caused by a blockage in an artery, thickening of the blood, or exposure to certain types of chemotherapy, environmental factors, or vibrating tools.
There’s also a rare tumor called angiosarcoma of the liver (HAS) that might make doctors suspect you’ve been exposed to significant amounts of VCM. This type of tumor can also be linked to chronic exposure to arsenic, as well as a type of imaging contrast dye made with thorium, which hasn’t been used in a long time.
What to expect with Vinyl Chloride Toxicity
A one-time exposure to vinyl chloride monomer (VCM), which can cause mild symptoms like dizziness and headaches, has not been proven to lead to long-term health issues. Workers who used to clean reactor vessels and were frequently exposed to high levels of VCM saw a slowdown in the progression of angiosarcoma of the liver (a rare type of liver cancer) when they were removed from these high-exposure environments. In some cases, their health even improved.
In a 1973 study of 1,294 workers heavily exposed to VCM, 11 cases of Hepatic Angiosarcoma (HAS), a rare type of liver cancer, were reported. This reflects an incidence rate much higher than that seen in the general population, due to their constant exposure to the substance.
However, there’s no standardized treatment for HAS though liver surgery, liver transplants, and chemotherapy are options for treatment. Unfortunately, despite these treatments, the survival rate after two years is just 3%.
Possible Complications When Diagnosed with Vinyl Chloride Toxicity
Exposure to hazardous materials in the workplace or environment usually results in minor complications, if it’s a one-time, mild exposure. However, a large one-time exposure could lead to problem with breathing and central nervous system, and in extreme cases, could even result in death. Workers who have been continuously exposed to these harmful substances prior to the regulations set in 1975 by the Occupational Safety and Health Administration (OSHA) may have developed serious conditions like lung cancer, liver cancer, brain cancer, and serious liver and lung diseases, particularly for those who work with vinyl chloride (VCM).
While it’s established that there is a strong association between these health problems and VCM exposure, it’s still a matter of debate whether VCM exposure directly causes these conditions. However, it’s worrying to point out that even in developing countries with weaker regulation of the plastics industry, serious lung disease continues to be reported among factory workers, indicating that significant exposure to harmful substances is still ongoing.
Common health risks associated with hazardous exposure:
- Breathing problems
- Central nervous system depression
- Potential death
- Angiosarcoma of the liver (AOL)
- Hepatic angiosarcoma (HAS)
- Cirrhosis
- Liver cancer
- Brain cancer
- Lung cancer
Preventing Vinyl Chloride Toxicity
Keeping workers safe from exposure to VCM, or vinyl chloride, is the duty of employers and the places they work. There’s a usual process that needs to be taken to lessen or completely avoid long-term exposure to VCM at work. Sometimes it may be necessary to get advice from specially trained people known to us as industrial hygienists or occupational medicine doctors, to find the best ways to decrease exposure to VCM at work.
Employers have to make sure workers know about the risks of exposure, including the fact that VCM can cause cancer; the right way to use personal protective equipment (PPE); the usual ways to lessen harm if there’s an accidental exposure; and what kind of regular health checks should happen every year.
