In labs that work with dangerous substances, it pays to design the best workflow

The saying “go with the flow” makes some sense in a stress-relief seminar, but not in a laboratory—that is, the idea of simply letting things follow the paths that come along does not always work in a lab. Nonetheless, labs do develop workflows, which simply emerge from how scientists perform processes or through engineered methods. Only the latter—a thought-out approach to how a lab works—can keep scientists consistently safe.

Just because some workflow exists in a lab doesn’t ensure that it’s a good one. “Workflow can have either a positive or negative impact on safety,” says Bryan Prince, a pharmacy workflow and design consultant at Lab·Red Pharmacy Consultants (Greenville, SC). “The most positive impact on chemical-handling workflow is when safety is at the core of the process and the question is asked: How does this affect safety?”

Bringing in new devices

Adding a new device to a lab can change the workflow. “Newer equipment often brings higher levels of efficiency to the process, but it is important that environmental and/or personnel exposure safety standards are not compromised,” Prince explains.

To ensure ongoing safety when new equipment is installed, the standard operating procedure (SOP) must be updated or completely redone. “The goal of establishing a safe workflow standard on the SOPs is part of a risk-management strategy to minimize exposures,” Prince says. Some questions to ask, according to Prince, are:

  • Does the equipment generate particles or gases?
  • Are there quantitative exposure levels that have been established on the chemical’s safety data sheets?
  • What are the proper personal protective equipment standards?
  • How is the equipment cleaned and/or decontaminated?

Improvements in analytical labs

Changing laws also impact safe workflows in analytical labs. “Common solvents that were previously viewed as having minimal or moderate health concerns have been reclassified, as more modern tests have indicated that many of these chemicals have been found to be known human carcinogenic molecules,” says Michael McGinley, technical manager at Phenomenex (Torrance, CA). “With this reclassification, the maximum occupational exposure limits of many of these solvents have been reduced hundreds or even thousands fold over previously existing levels, thus necessitating a complete reevaluation of how certain chemicals are used in a lab as well as how to best provide personal protection for those in a lab.”

As an example, McGinley points out that many sample-preparation methods use chlorinated solvents, such as dichloromethane and chloroform. These compounds are also used as mobile-phase solvents. “With the reduction of exposure limits, special care must be taken in minimizing contact with such solvents as well as avoiding the volatile vapors emitted from solvent containers,” McGinley explains. In some cases, the workflow must move some steps into a fume hood. Nonetheless, that won’t always be enough. As McGinley notes, “instrument use and their associated waste streams must all be considered in generating a safe analytical laboratory environment.”

Refining the flow

In some cases, as noted above, a lab’s workflow really does involve flow. “The best way for a lab to improve safety is to do an analysis of its primary and secondary engineering controls,” Prince explains. “A primary engineering control (PEC) is most often negative-pressure containment equipment—generically referred to as hoods—that create a physical barrier between the technicians and the chemicals.” With directional airflow, the PEC protects scientists from chemical exposure. “It is important to marry the correct PEC with the specific process,” Prince points out. As an example, he describes a nonsterile powder-handling process where the safety goal is to protect the worker, and that takes only “a negative-pressure containment ventilated enclosure, which is a low-flow containment enclosure that does not disrupt powders during manipulation.” Other applications require a biosafety cabinet.

In a secondary engineering control (SEC), positive or negative pressure is applied to a room or an entire laboratory. “If the lab is handling hazardous drugs, it is best if the SEC is under negative pressure,” Prince says. “Increasing the number of air changes per hour and improving air quality in the room is a good methodology, but consideration to the processes and chemicals is important, as well as established industry compliance standards.” To dig deeper into these elements of workflow, Prince recommends his white paper on the topic.1

Steps toward safety

The necessary steps to making a lab’s workflow safer always depend on the lab and what it does, but some general approaches do exist. “Having a discussion with their organization’s safety manager is always a good idea, and eliminating the use of toxic substances would also be helpful,” McGinley says. “Unfortunately, that is not always practical.”

Where a workflow must include toxic solvents, such as in some applications of high-performance liquid chromatography (HPLC), special steps should be taken to make the process as safe as possible. “As part of providing better solutions to lab researchers, Phenomenex has recently introduced SecurityCAP safety caps to help eliminate exposure to volatile HPLC mobile phases and HPLC waste,” McGinley says. “SecurityCAP is an assortment of vented and filtered bottle caps that form a seal over most common HPLC mobile phase reservoir bottles, as well as most HPLC waste containers.” Using these caps, scientists can virtually eliminate any solvent vapors from HPLC systems. McGinley says the caps, “are just one part of a holistic program that one can incorporate toward improving the safety of an analytical laboratory.”

Many elements of a lab’s workflow—from airflow and powder containment to solvent handling and special devices—impact safety. One philosophy worth remembering is: No single step can make a lab’s workflow entirely safe, but no step should be ignored.

Reference

  1. Prince, B. Workflow strategies to minimize exposure to hazardous drugs in the compounding pharmacy. 2017; https://learn.nuaire.com/white-papers/minimizeexposure-to-hazardous-drugs.

Mike May is a freelance writer and editor living in Texas. He can be reached at [email protected].