Case Study: Effective Management of Exposure Risk in Historic Building Refurbishment

In the ever-evolving realm of construction and urban development, repurposing and modernising old buildings presents unique challenges and hidden risks. A testament to this fact is our recent investigation of a historic commercial building, poised on the brink of a comprehensive refurbishment project. The structure, a poignant snapshot of architectural practices of yesteryears, still housed the original animal hair plaster—a construction material laden with potential health hazards, particularly when disturbed.

Animal hair plaster, once a prevalent building material, was created by integrating animal hair into a mixture of lime and sand. While structurally effective, it has a hidden danger: it can harbour Bacillus anthracis, the bacterium responsible for causing anthrax. Indeed, anthrax is a potentially fatal disease, known to reside dormant for decades in animal hair, and can be released when such old plaster is disturbed, leading to inhalation or dermal exposure.

The risk associated with Bacillus anthracis is gravely significant. In its inhalational form, anthrax is particularly lethal, causing severe flu-like symptoms that can rapidly progress to severe breathing problems and shock. Moreover, cutaneous anthrax, contracted through skin exposure, although less lethal, can still lead to significant illness and complications if not promptly treated. For construction workers involved in refurbishment projects, such exposure could pose severe occupational health hazards—a reality that underscores the necessity of our investigation.

Methodology

Our approach to this complex task was meticulous, employing a top-to-bottom investigation of the entire building, aimed at identifying all areas where animal hair plaster had been used in the original construction. We initiated this by systematically surveying each floor, wall, and ceiling, understanding the potential historic layers and building elements that could contain the material of concern.

Collection of representative samples was the next critical phase in our methodology. Throughout the building, particularly in the zones scheduled for refurbishment or demolition, we meticulously gathered plaster samples for laboratory analysis. Given that we aimed to understand the risks associated with the impending construction work, the focus was strictly on those areas that would be significantly disturbed during the refurbishment process.

It's worth noting that, in historic buildings, certain decorative surfaces may be under preservation orders and hence, sampling from these areas might not be possible or indeed necessary. In such scenarios, where work on protected surfaces is typically avoided to maintain their historical integrity, the risk of disturbing potential Bacillus anthracis reservoirs is mitigated. Hence, our sampling process conscientiously circumvents such surfaces, focusing instead on areas prone to significant disturbance during the refurbishment activities. This tailored approach ensures the mitigation of risks while honouring the historical significance of the structure.
  

Findings

Our findings from the investigation were encouraging; no presence of Bacillus anthracis was detected in the samples. This crucial result leads us to conclude that the risk of exposure to this pathogen is relatively low during the refurbishment process. However, the task of working with historic plaster containing animal hair isn't devoid of health and safety concerns and thus, the protection of workers remains paramount.

The dust that arises during work on these materials may contain potentially allergenic organic matter, posing respiratory risks to the workers. Furthermore, the plaster dust itself can be harmful if inhaled, due to its crystalline silica content, a substance known to contribute to respiratory diseases such as silicosis, lung cancer, and chronic obstructive pulmonary disease (COPD).

To mitigate these health risks, we recommend several control measures. Workers should be equipped with protective gear such as overalls and P3 respirators, designed to filter out the harmful particulates from the air they breathe. Implementing good practice methods like avoiding dry sweeping will minimise the amount of dust in the air. Damping down surfaces prior to work can further reduce dust generation.

Employing effective dust extraction systems and ensuring adequate ventilation during the works can also be beneficial in controlling dust levels. Moreover, it's advisable that workers wash their hands and face thoroughly before eating, drinking or smoking to prevent ingestion of dust.

Post-work, protective clothing should be properly cleaned or disposed of safely to avoid contamination of personal clothing and vehicles. Regular health surveillance should be a standard protocol to detect any early signs of health issues related to dust exposure.

In conclusion, while the risk of exposure to Bacillus anthracis in this scenario is relatively low, careful consideration must be given to the potential risks from dust exposure. By employing the recommended control measures, workers' safety and health can be ensured during the refurbishment process.

Work with Anthrax Contaminated Plaster

 
Working with Bacillus anthracis-contaminated plaster involves significant risk and requires rigorous health and safety measures. Bacillus anthracis is the bacterium responsible for causing anthrax, a severe and potentially deadly disease, and can survive in a dormant state in the environment, including plaster, for many years. Here are some control measures that should be in place:

1. Personal Protective Equipment (PPE): Workers should be equipped with full-body protective clothing, including coveralls, gloves, and boot covers that are either disposable or easily decontaminated. Respiratory protection such as a P3 filter respirator or a powered air-purifying respirator (PAPR) should be worn to protect against airborne spores. Eye protection such as goggles or face shields can protect against splashes or dust.
 
2. Controlled Environment: The working area should be isolated and controlled to prevent the spread of contamination. This may involve the use of negative air pressure and physical barriers like plastic sheeting. Ventilation systems should be shut off to prevent the spread of spores.

3. Decontamination: All tools, equipment, and work surfaces should be regularly decontaminated. An effective sporicidal agent, such as a solution of bleach, should be used.

4. Safe Waste Disposal: All waste materials and disposable PPE should be considered as biohazardous waste and should be properly contained and disposed of in accordance with local regulations for infectious waste.

5. Health Monitoring: Workers should be monitored for any symptoms of anthrax, and medical treatment should be available immediately if symptoms are detected. In certain cases, workers may be vaccinated against anthrax before beginning the work.

6. Training: Workers should be adequately trained about the risks of working with Bacillus anthracis, the symptoms of anthrax, and the appropriate safety measures to take.

7. Regulation Compliance: All work should be done in accordance with local, state, or national regulations regarding the handling of infectious materials.

8. Risk Assessment: Regular risk assessments should be conducted to identify any potential hazards and to ensure that the necessary control measures are in place and effective.

9. Hygiene Practices: Workers should follow good hygiene practices, including hand washing before eating, drinking, smoking, or using the bathroom, and showering at the end of the work shift.
 
Remember, it's crucial to consult with an occupational health professional or a biosafety specialist before beginning work with Bacillus anthracis-contaminated materials to ensure all safety measures are appropriately implemented.

Value delivered

Through our comprehensive assessment and diligent risk management strategies, we were successful in delivering significant value to our client. The first layer of this value was the correct management of exposure risk to Bacillus anthracis. By accurately identifying all areas where animal hair plaster was used and effectively screening them for the bacteria, we alleviated concerns about this severe health threat and helped create a safer environment for all workers involved in the refurbishment project.

In addition to dealing with the potential Bacillus anthracis risk, we brought attention to other health and safety concerns associated with working with historic plaster, such as allergenic organic materials and crystalline silica dust. Our thorough approach has underscored the importance of protective measures like wearing PPE, implementing good practice methods like damping and avoiding dry sweeping, and applying appropriate dust control measures.

Further value was added through our efforts to ensure staff safety. By highlighting the necessity for protective clothing, P3 respirators, and diligent hygiene practices, we have made a tangible contribution to reducing the health risks for the workers on site. Our recommendations have set the basis for safety protocols and training programs that will not only benefit workers during this refurbishment project but will also enhance the client's overall approach to occupational safety.
 
Finally, our efforts have contributed to mitigating the potential legal and financial implications for the client associated with mishandling hazardous substances and related health risks. By clearly outlining the control measures necessary for safe operations, we've helped the client to comply with health and safety regulations, thereby avoiding potential penalties and reputational damage.

In conclusion, our services have provided a comprehensive solution that addresses both immediate and long-term safety concerns, enhancing the overall health and safety culture of the client's operations. This goes beyond the mere identification of hazards and extends to shaping practices that prioritise the well-being of every individual involved in the project.