Mitigating bioaerosol risks in pharma plants

May 6, 2024
Amid limited guidance from regulators, facility designers can deliver significant safety advantages by tackling risks at the source

In 1976, public health awareness underwent a significant shift when a new strain of bacteria infected hundreds of attendees at an American Legion convention in Philadelphia. The lethal bacteria, dispersed through aerosolized droplets, were eventually traced back to a hotel cooling tower where they proliferated before spreading through the ventilation system. 

The widely covered Legionnaires' disease outbreak brought national attention to the role of bioaerosol exposure in spreading infectious diseases. Nearly 50 years later, the public health risks associated with bioaerosols persist. 

Improved ventilation filters, personal protective equipment and vaccines have reduced some of the risks associated with bioaerosols. Attention in the pharma industry has now turned to identifying and controlling the origins of bioaerosols. While cooling towers and aeration units are essential to the operation of pharma plants, they are also environments that foster the growth and dissemination of pathogen-containing and antibiotic-resistant microorganisms.

In the absence of regulations specifically established for managing bioaerosol risks, pharma manufacturers need to find their own solutions. Fortunately, pharma facility designers can deliver significant safety advantages by tackling risks at their source.

Getting to the source

Cooling towers serve as ideal breeding grounds for microbes because of their warm and moist environment. Legionella, the bacteria linked to Legionnaires' disease, is found in as many as 60% of cooling towers.

Wastewater treatment systems, specifically aeration units, can release pathogen-laden bioaerosols when breaking down organic matter. Studies have found seasonal variations in bioaerosol concentrations in wastewater, raising important questions about treatment alternatives. 

Currently, manufacturers primarily rely on their own resources for solutions. While some state and local agencies are considering the impact of bioaerosols on facility design, there is still a lack of industrywide standards and protocols.  

Bioaerosol risk management  

While there are no regulations specifically established for managing bioaerosol risks, there are strategies to follow when designing new facilities or upgrading existing ones. Risk characterization studies, for instance, can provide valuable insights into the potential hazards posed by cooling tower emissions. Additionally, strict compliance with building code regulations regarding cooling tower setbacks and design can effectively reduce public health hazards. 

Similarly, wastewater treatment systems can incorporate modifications aimed at reducing bioaerosol releases. Measures such as containment structures, as well as improvements in ventilation and filtration systems, can be implemented to limit dispersion. 

To prevent the spread of infectious diseases both within and outside pharma plants, some pharma companies are also pursuing: 

Bioaerosol surveillance: Advancements in technology — such as real-time air quality monitors, remote sensors and predictive modeling — are making bioaerosol surveillance more accessible and accurate. These modern tools can detect bioaerosols in the air, on surfaces and on equipment. Optical particle counters are capable of distinguishing between different particle sizes and microbial compositions, offering valuable insights into airborne contamination levels. 

Drones equipped with sensors enable pharmaceutical companies to conduct aerial surveys, analyzing bioaerosol dispersion patterns and pinpointing potential contamination sources. Remote sensing systems facilitate surveillance across expansive manufacturing sites. By leveraging predictive modeling, machine learning and advanced data analytics, it’s even possible to forecast bioaerosol dispersion and predict how best to mitigate releases. 

‘Smart’ approaches to antimicrobial resistance: Bioaerosols that carry antibiotic-resistant microbes and circulate within manufacturing environments pose a threat of contaminating drug formulations, equipment and personnel. The challenge is to develop bioaerosol management strategies enabling swift responses to potential contamination incidents. 

One possibility is a 'smart' airflow control and ventilation system that automatically adjusts airflow rates, activates filters and triggers alarms based on the bioaerosol levels detected. Alternatively, those preferring a less technology-dependent approach could prevent cross-contamination by isolating bioaerosol-generating processes from other areas of the plant. 

Bolstered resilience: Now is a great time to build resistance to bioaerosol-related risks in supply chains and manufacturing processes. Initiating a risk assessment encompassing raw materials, packaging, logistics and distribution channels serves as a prudent starting point. This can be helpful in identifying supply chain vulnerabilities and developing risk mitigation strategies against bioaerosol-related threats. 

Inside the plant, backup power generators and additional design redundancies enable critical operations to continue amid bioaerosol-related disruptions. To reduce reliance on a single water source, some manufacturers are integrating multiple water treatment systems and supply options. Others are opting for modular layouts that can be adapted to changing bioaerosol risks. Flexible facility designs make it easier to isolate contamination and adjust workflows to minimize bioaerosol exposure. Fostering a culture of continuous improvement and adaptation helps maintain the currency and efficacy of bioaerosol control measures. 

The bottom line 

Even amid limited guidance from regulators, pharma facility designers can deliver significant safety advantages by tackling risks at their source. The industry's products and reputation, as well as public health, all stand to benefit. The tools are available, the time to begin is now. 

About the Author

Bill Celenza | Senior Process Engineer, Burns & McDonnell

Bill Celenza, PE, is a senior process engineer at Burns & McDonnell who designs environmental treatment systems and addresses regulatory compliance issues for pharmaceutical and other industrial facilities.