Rachael provides a comprehensive guide to understanding and avoiding dichloromethane.

DICHLOROMETHANE (DCM), also known as methylene chloride, is a common chemical used in various industries, particularly in sprayable adhesives. However, despite its widespread use, DCM poses significant health risks that are often overlooked.

If you’re working with or around DCM-based products, it’s crucial to understand these risks and take steps to protect yourself and others.

In this blog, we’ll explore what you need to know about DCM, how to identify products containing this chemical, and why switching to DCM-free alternatives is a smart move.

What is DCM and why should you be concerned?
DCM isn’t the adhesive itself, but the solvent carrier used in many sprayable adhesive products. Its primary function is to deliver the adhesive to a surface and then evaporate, leaving the adhesive behind.

While this might sound harmless, the reality is far more concerning. DCM is a volatile organic compound (VOC) that can quickly vaporise and become airborne, creating a significant inhalation hazard in any environment where it’s used.

Inhalation hazard
The most common way people are exposed to DCM is through inhalation. Since DCM vapours are heavier than air, they tend to accumulate at ground level, particularly in poorly ventilated spaces. This makes it especially dangerous in occupational settings where workers are exposed to high concentrations.

The danger is amplified in confined spaces like basements or small rooms where ventilation is limited. In such environments, DCM can build up to toxic levels very quickly, leading to acute exposure incidents that can result in immediate and severe health effects.

Carcinogenic properties
DCM is classified as a carcinogen, meaning it carries the hazard statement ‘suspected of causing cancer.’ Prolonged or repeated exposure can increase the risk of developing serious health issues, including cancer.

The International Agency for Research on Cancer (IARC) has classified DCM as a Group 2A carcinogen and workers in industries where DCM is used have reported higher incidences of certain types of cancers, particularly those affecting the liver, lungs, and pancreas. This long-term risk adds a layer of complexity to the decision of whether to use DCM-containing products, especially when safer alternatives are available.

Carbon monoxide production
Once inhaled, DCM is metabolised by the body into carbon monoxide, a toxic gas that displaces oxygen in the blood. This can lead to oxygen deprivation in vital organs like the heart and brain, with potentially fatal consequences.

Carbon monoxide is particularly dangerous because it binds to haemoglobin in the blood much more effectively than oxygen does, preventing the oxygen from being delivered to tissues.
This can result in symptoms ranging from mild headaches and dizziness to severe neurological damage, cardiac arrest, or even death in cases of extreme exposure.

Odourless danger
Unlike other toxic chemicals, DCM is almost odourless. This means you could be exposed to harmful levels without even realising it until physical symptoms, such as headaches, dizziness, or more severe conditions like kidney problems or cancer, begin to appear.

The lack of a strong odour makes DCM particularly dangerous because it can easily go undetected. This is one reason why workplace exposure limits are so important – DCM’s effects can be cumulative, and even low-level exposure over time can lead to significant health risks.

The health effects to watch for
Exposure to DCM can result in a range of health issues, including:

• Headaches: A common symptom of acute exposure, often accompanied by dizziness and fatigue.
• Skin rashes: DCM can cause irritation upon contact with the skin, leading to rashes, burns, or dermatitis.
• Dizziness: Inhalation of DCM vapours can lead to dizziness, light-headedness, and even fainting spells, especially in poorly ventilated areas.
• Coughing or wheezing: Respiratory symptoms such as coughing, wheezing, and shortness of breath are common, particularly in people with pre-existing lung conditions.
• Blurred vision: High levels of exposure can affect vision, causing blurred or double vision, which may be temporary or persistent.
• Kidney problems: Chronic exposure has been linked to kidney damage, which may present as decreased urine output, swelling in the legs, or elevated blood pressure.
• Cancer: As mentioned, prolonged exposure to DCM is associated with an increased risk of cancer, particularly of the liver, lungs, and pancreas.
  
  If you experience any of these symptoms and suspect DCM exposure, seek medical attention immediately. Early intervention can mitigate the risks, but the best protection is prevention.
  
  Identifying DCM-adhesive products
  To avoid accidental exposure, it’s important to know how to identify products that contain DCM.
  
  Here are some tips:
  Check the safety section: Products containing DCM will typically include the hazard code H351, which indicates that the substance is ‘suspected of causing cancer’. This is a critical identifier and shouldn’t be ignored.
  
  Look for danger warnings: The product label will also include the warning ‘DANGER: Contains dichloromethane’ or ‘methylene chloride.’ This is a clear indication the product poses significant health risks.
  
  Pictogram alert: A red diamond pictogram with a person and an exploding chest inside signifies the presence of a carcinogen, including DCM. This visual cue is an easy way to identify dangerous chemicals at a glance.
  
  Consult the safety data sheet (SDS): If you’re unsure about a product, request the SDS from your distributor or the manufacturer. Pay special attention to Section 2, which lists hazard indications, and Section 8, which covers personal protective equipment (PPE) and exposure controls.
  
  The SDS will also provide information on first-aid measures, accidental release measures, and proper storage and disposal practices. Remember, key safety information is also located on the reverse of the can, so make sure to check there before use.
  
  Alternatives to DCM
  Given the serious health risks associated with DCM, many industries and consumers are making the switch to DCM-free alternatives. These alternatives often use fewer volatile solvents or water-based adhesives, which significantly reduce or eliminate the hazards posed by DCM.
  
  For instance, many companies now offer sprayable adhesives that use acetone or ethanol as solvents – both of which are far less hazardous than DCM.
  
  When choosing an alternative, it’s essential to consider the specific requirements of your application. While DCM-based adhesives are popular for their quick-drying properties and strong bonds, modern alternatives can often match or even exceed these performance characteristics without the associated health risks.
  
  Consulting with your supplier or a safety professional can help you identify the best DCM-free products for your needs.
  
  Protective measures when working with DCM
  If you must work with DCM-containing products, taking the following protective measures can help reduce your risk:
  Use adequate ventilation: Always work in a well-ventilated area to prevent the accumulation of DCM vapours. Mechanical ventilation systems, such as fume hoods or exhaust fans, can help remove airborne contaminants.
  
  Wear personal protective equipment (PPE): Appropriate PPE, including gloves, goggles, and respirators, should be used when handling DCM. Make sure the respirator is rated for organic vapor protection.
  
  Limit exposure time: Reduce the amount of time spent using DCM-containing products and take regular breaks in fresh air to minimise cumulative exposure.
  
  Store chemicals properly: DCM should be stored in tightly sealed containers in a cool, well-ventilated area away from sources of heat or ignition.
  
  Training and awareness: Ensure all workers who might come into contact with DCM are trained on its hazards and the proper safety protocols. Regular safety drills and refreshers can keep safety top of mind.
  
  In conclusion dichloromethane (DCM) is a potent chemical with serious health risks that cannot be ignored. While it plays a crucial role in many industrial applications, the dangers it presents – from carcinogenic properties to its ability to convert into carbon monoxide – make it a substance that requires careful handling and respect.
  
  The potential for exposure through inhalation, particularly in poorly ventilated spaces, adds to the risk profile of this chemical, making it essential for those who work with or around it to take appropriate protective measures.
  
  By being vigilant about identifying products that contain DCM, adhering to safety protocols, and considering the switch to safer alternatives, you can significantly reduce the risks associated with this hazardous chemical.
  
  Remember, the best way to protect your health and the health of those around you is to stay informed and proactive. Understanding the risks of DCM is the first step in ensuring a safer working environment and making informed decisions that prioritise long-term health and safety.
  Rachael Morgan is sales and marketing manager, Quin Global