Isocyanate Exposure monitoring

Ensure that your staff are safe from the hazards of exposure to Isocyanates by workplace air monitoring.

Understanding the Hazards of Isocyanates in the Workplace

Isocyanates are a group of chemicals commonly used in the production of polyurethane products such as foams, adhesives, coatings, and insulation materials. While these substances are invaluable in various industrial processes, they also pose significant hazards to human health. Understanding isocyanate exposure by monitoring is crucial for employers and workers alike to ensure safety in the workplace.

Exposure to isocyanates primarily occurs through inhalation or skin contact during manufacturing, application, or removal of products containing these chemicals. Furthermore, the hazards associated with isocyanates can range from mild irritation to severe respiratory issues and even life-threatening conditions. Here are some key hazards:

Respiratory Issues: Inhalation of isocyanates can lead to respiratory problems such as coughing, wheezing, chest tightness, and difficulty breathing. In addition, prolonged exposure or exposure to high concentrations may cause asthma or exacerbate pre-existing respiratory conditions.

Skin Irritation and Sensitization: Direct contact with isocyanates can cause irritation, redness, itching, and in severe cases, chemical burns. Furthermore, repeated exposure may lead to sensitization. This is where the immune system becomes hypersensitive to the chemical, resulting in allergic reactions upon subsequent exposure.

Eye Irritation: Isocyanates can cause irritation, redness, and watering of the eyes upon contact. Furthermore, prolonged exposure or exposure to high concentrations may lead to more severe eye damage, including corneal injury.

Systemic Effects: In addition to local effects, isocyanate exposure can also have systemic effects on the body. Studies have linked high levels of isocyanate exposure to potential damage to the liver, kidneys, and central nervous system.

Carcinogenic Potential: Some isocyanates, particularly aromatic isocyanates like MDI (methylene diphenyl diisocyanate), have been classified as potential carcinogens by regulatory agencies. Prolonged or repeated exposure to these substances may increase the risk of cancer, particularly lung cancer.

Exposure Limits for Isocyanate

Isocyanate exposure Limits

In the UK, the COSHH Regulations 2002 sets out exposure limits for various hazardous substances including isocyanates. Specifically, the Health and Safety Executive (HSE), which enforces COSHH, provides Workplace Exposure Limits (WELs) for isocyanates to protect workers from the health hazards associated with these chemicals.

Isocyanates, all (as NCO)
Except methyl isocyanate

long-term exposure limit (as an 8-hour time weighted average) – 0.02mg.m^-3

short-term exposure limit (as a 15-minute time weighted average) – 0.07mg.m^-3

Methyl isocyanate (as ~NCO)

No long-term exposure limit

short-term exposure limit (as a 15-minute weighted average) – 0.02ppm

These exposure limits are concentration limits of isocyanates in the workplace designed to prevent adverse health effects. Health effects such as respiratory irritation, sensitization, and other systemic effects associated with exposure to these chemicals.

It’s important for employers to monitor air quality regularly in workplaces where workers use isocyanates to ensure that exposure levels stay below the specified WELs. Additionally, implementing engineering controls, providing appropriate personal protective equipment, and conducting comprehensive training programs are essential to minimizing the risk of exposure to isocyanates and ensuring the health and safety of workers.

Monitoring Exposure to Isocyanates

In the United Kingdom, exposure to isocyanates in the workplace is typically measured through air sampling and biological monitoring.

Air Sampling. Air sampling involves the collection of air samples from the workplace environment to measure the concentration of airborne isocyanates. This is done using personal air sampling pumps attached to workers’ clothing. Static sampling in the vicinity of potential sources of isocyanate exposure is also possible. A laboratory then analyses the collected samples using specialized equipment to quantify the concentration of isocyanates present. Air sampling provides direct information about workers’ exposure to isocyanates during their daily activities.

Biological Monitoring. Biological monitoring involves analyzing biological samples, such as urine or blood, from exposed workers to assess their internal exposure to isocyanates. The body metabolises Isocyanates in the body and eliminates them through urine. This makes urine samples a common choice for biological monitoring. The presence of specific metabolites of isocyanates in biological samples indicates recent exposure to these chemicals. Biological monitoring provides complementary information to air sampling and can help evaluate the effectiveness of control measures in reducing exposure levels.

Both air sampling and biological monitoring are valuable tools for assessing occupational exposure to isocyanates and ensuring compliance with exposure limits set by regulatory authorities such as the Health and Safety Executive (HSE) in the UK. Employers are responsible for conducting regular monitoring of isocyanate exposure in workplaces where these chemicals are used. They are also responsible for taking appropriate measures to minimize exposure risks and protect the health and safety of workers.

Controlling Isocyanate Exposure

Control of exposure to isocyanates in the workplace is usually by a combination of monitoring, engineering controls, administrative measures, and also the use of personal protective equipment (PPE). Here are some key strategies for controlling exposure to isocyanates:

Engineering Controls:

Ventilation Systems. Implementing local exhaust ventilation (LEV) systems near sources of isocyanate emissions can effectively capture and remove airborne contaminants before they disperse into the workplace atmosphere.

Enclosures and Containment. Using enclosed systems or containment measures during processes involving isocyanates can minimize the release of airborne particles and reduce the risk of exposure to workers.

Substitution and Process Modification. Where feasible, substitute hazardous isocyanate-containing products with safer alternatives or modify processes to minimize the generation of airborne contaminants.

Administrative Control

Workplace Monitoring. Regular isocyanate exposure monitoring and biological monitoring helps assess the effectiveness of control measures and identify areas for improvement.

Work Practices. Implementing safe work practices, such as minimizing spraying or generating aerosols, using proper application techniques, and ensuring adequate ventilation during tasks involving isocyanates, can help reduce exposure risks.

Training and Education. Providing comprehensive training programs to workers on the hazards of isocyanates, safe handling procedures, proper use of PPE, and also emergency response protocols promotes awareness and ensures compliance with safety regulations.

Personal Protective Equipment (PPE):

Respiratory Protection. Workers should wear appropriate respiratory protective equipment, such as air-fed breathing apparatus. It should be noted that filtered devices are not appropriate.

Protective Clothing and Gloves. Workers should wear chemical-resistant gloves, coveralls, and other protective clothing to prevent skin contact with isocyanates, minimizing the risk of irritation, sensitization, or absorption through the skin.

Eye and Face Protection. Workers must wear safety goggles or face shields to protect against splashes or aerosol exposure to the eyes and face.

Hygiene Practices:

Personal Hygiene. Encourage workers to practice good personal hygiene. This includes practices such as washing hands thoroughly with soap and water before eating, drinking, or smoking, and avoiding skin contact with contaminated surfaces or clothing.

Facility Cleaning. Implement regular cleaning and decontamination procedures for work surfaces, equipment, and tools to prevent the accumulation of isocyanates. This will minimize the risk of exposure through inadvertent contact.

By implementing a combination of these control measures tailored to the specific hazards and processes in their workplace, employers can effectively mitigate the risks associated with exposure to isocyanates and therefore ensure a safe and healthy working environment for their employees. Regular evaluation and refinement of control measures based on ongoing monitoring of isocyanate exposure and feedback are essential for maintaining effective exposure control over time.