Diisocyanates - Hazards and Controls

?Diisocyanates (usually referred to as isocyanates in the UK) are a family of highly reactive, low molecular weight chemicals. They are widely used in the manufacture of flexible and rigid foams, fibres, coatings such as paints and varnishes, and elastomers, and are increasingly used in the automobile industry, autobody repair, and building. While they are valuable in various industrial applications, diisocyanates pose several health and safety hazards that need to be carefully managed. The main hazards associated with diisocyanates include:

Diisocyanate Hazards

1. Respiratory Hazards

?? - Asthma: Diisocyanates are known respiratory sensitizers and can cause occupational asthma. Inhalation of diisocyanate vapours, aerosols, or dusts can lead to severe asthmatic reactions, even at low levels of exposure.

?? - Irritation: Exposure to diisocyanates can cause irritation of the respiratory tract, leading to symptoms such as coughing, wheezing, and shortness of breath.

2. Skin Hazards

?? - Sensitization: Skin contact with diisocyanates can lead to allergic contact dermatitis. Once sensitized, individuals can react to even very low levels of exposure, with symptoms such as redness, itching, and swelling.

?? - Irritation: Diisocyanates can cause skin irritation, resulting in rashes and other dermatological issues.

3. Eye Hazards

?? - Irritation: Exposure to diisocyanate vapours or direct contact with liquid diisocyanates can cause severe eye irritation, redness, and tearing.

?? - Damage: In severe cases, exposure can result in chemical burns or permanent eye damage.

4. Acute Toxicity

?? - Inhalation: High-level inhalation exposure to diisocyanates can lead to acute respiratory distress, pulmonary oedema, and other severe respiratory conditions.

?? - Ingestion: Accidental ingestion of diisocyanates is highly toxic and can cause severe gastrointestinal distress, chemical burns, and systemic toxicity.

5. Chronic Health Effects

?? - Chronic Respiratory Issues: Long-term exposure to diisocyanates can lead to chronic respiratory conditions, reduced lung function, and permanent lung damage.

?? - Carcinogenicity: Some studies suggest a potential link between long-term diisocyanate exposure and an increased risk of cancer, though the evidence is not conclusive.

6. Environmental Hazards

?? - Aquatic Toxicity: can be toxic to aquatic life. Improper disposal or spillage can lead to contamination of water sources and harm to aquatic ecosystems.

?

Safety Measures

To mitigate these hazards, the following safety measures should be implemented:

Engineering Controls: Use adequate ventilation systems, such as local exhaust ventilation, to reduce airborne concentrations of diisocyanates.

Protective Equipment (PPE): Wear appropriate protective gear, including gloves, respirators, eye protection, and protective clothing, to prevent skin and respiratory exposure.

Work Practices: Implement proper work practices, such as handling diisocyanates in well-ventilated areas, minimizing the generation of aerosols, and following safe handling and storage procedures.

Training and Awareness: Provide thorough training to workers on the hazards of diisocyanates, proper use of PPE, and emergency procedures.

Diisocyanate Awareness Training is now a mandatory requirement for all workers potentially exposed to diisocyanates in the course of their work (such as spray painters, engineers, etc.)

Exposure Monitoring: Regularly monitor airborne concentrations of diisocyanates in the workplace to ensure they remain below recommended exposure limits.

Medical Surveillance: Implement a medical surveillance program to monitor workers' health, particularly respiratory function, and identify early signs of sensitization or other health effects.

?

By adhering to these safety measures, the risks associated with diisocyanates can be significantly reduced, protecting the health and safety of workers and the environment.