The potential hazards from biological facilities handling infectious agents are immense, and ensuring the safety of these high containment level laboratories is of utmost importance. With the emergence of various pathogens, researchers are continually seeking new methodologies to evaluate risks associated with biological handling. One such method gaining traction is the Layers of Protection Analysis (LOPA), which offers comprehensive insights to safeguard against unplanned hazardous scenarios.
Developed as part of the drive for functional safety, LOPA is primarily utilized within the process industries, such as oil and gas, to establish how secure current safety measures are. According to the authors of the article, LOPA can potentially be adapted to the biosafety sector to evaluate the efficacy of safeguards against uncontrolled releases of pathogens. They note, "The LOPA method has been used extensively in the process industries as a useful tool to manage and understand risk and to demonstrate if the facility is ‘safe’ to operate, but much less so in the biosafety sector."
This adaptation poses the challenge of determining risk thresholds appropriate for biological materials, where the consequences could extend from localized outbreaks to significant health crises affecting human populations or livestock. The LOPA process involves identifying hazardous scenarios, evaluating the initiating events leading to such scenarios, calculating the effectiveness of current safety mechanisms, and determining any additional safety functions required.
To initiate the LOPA process, researchers first identify hazardous scenarios and determine acceptable risk frequencies. For example, the loss of pressure within containment facilities could lead to the dangerous escape of aerosolized pathogens. Additional scenarios might include faults with effluent treatment systems or failures to incinerate contaminated waste adequately. Under this methodology, the severity of these scenarios is properly quantified by estimating infection probabilities based on the characteristics and routes of infection of different pathogens. Notably, minimum infective doses (MID50) are factored to ascertain how many pathogens are required for infection to occur.
Hazard scenarios deemed suitable for LOPA must disclose the mechanics of infection to determine effective interventions. The authors explain, "The probability of infection is dependent upon several factors... the route of infection... the stability of the pathogen with respect to outside temperature, humidity etc." This layered analysis ensures researchers maintain stringent control over potential biohazards, minimizing the risk to laboratory personnel and the community.
The next step is identifying possible initiating events, such as mechanical failures or human errors. Specific initiating events pertinent to microbiological facilities might include blockages of filters, electrical failures, or natural disasters like floods—each carrying distinct frequencies based on the facility's past experiences. The frequencies, alongside corresponding independent protection layers (IPLs), help devise effective measures against these initiating events.
Independent protection layers vary based on their active or passive nature. Active protection might include sensors prompting alarms, whereas passive measures could consist of structural safeguards like blast walls. The effectiveness of each layer is determined by its Probability of Failure on Demand (PFD), which provides insight concerning the reliability and necessary response strategies whenever biohazards are present.
Conditional modifiers also come to play, as they influence the probability of the hazardous event occurring following initiating factors. These may involve aspects such as the time of exposure or the likelihood of pathogen exposure within the facility’s environment.
LA study’s success is determined when organizations complete these steps adequately, making necessary adjustments based on the calculated intermediate risk frequencies compared to their target frequencies. If the mitigation does not meet acceptable thresholds, organizations can implement Safety Instrumented Functions (SIFs) to reduce risks. The authors summarize the process, stating, "LOPA methodology prompts organizations to think about the hazards and risks inherent to their facilities and to reconsider the effectiveness of current safeguards."
The overarching aim of integrating LOPA within high containment facilities is to establish resilient safety protocols capable of reducing the frequency and potential impact of pathogen releases. By offering comprehensive guidelines for assessing risks associated with pathogenic agents, the LOPA method serves as pivotal for the future operations of biological establishments. The authors conclude, "With the right mentality, culture, and tools, the authors hope the LOPA methodology will become integral to reducing the frequency and impact of incidents involving unplanned release of pathogens from containment facilities."