A Guide To Understanding The Importance Of Powder & Vapor Containment

By Dr. Bob Haugen, Director of Product and Technology Development, and Dr. Allan Goodman, Regional Sales Manager

Maintaining safe and non-toxic sterile work environments is a top concern for employers across a wide spectrum of industries – from pharmaceutical manufacturers to first responders to furniture companies. However, what constitutes clean, hazard-free air may differ from sector to sector depending on the raw materials used. Common contaminants include visible dust, very fine powders, and molecular vapors.

In underregulated fields, employers may lack the guidance needed to make informed decisions on how to assess air quality or to add the infrastructure and engineering controls to mitigate exposure to unsafe levels of contaminants. In this paper, we will define the characteristics which make vapors and powders dangerous, discuss ways of detecting these agents, and review key methods shown to effectively contain these hazardous materials away from employees charged with manipulating them. Many containment solutions are available which mitigate inhalation risks and keep your team healthy and out of harm’s way.

What is an Inhalation Hazard?

Powder inhalation hazards come in a wide variety of forms. In the pharmaceutical industry, active pharmaceutical ingredients (APIs) are some of the most common. Since APIs are designed to trigger a reaction in the human body, inhaling their associated dust in large quantities can be extremely dangerous. Other powder inhalation hazards might appear in workflows where fine powders are being generated during production, i.e., woodwork, metal work, industrial grinding, the grinding of highly potent pharma ingredients, food production, and more. Alternately, there are slower acting chronic inhalation hazards like asbestos, where symptoms and associated diseases can take decades to develop.

Vapor inhalation hazards can also pose serious health threats due to their rapid absorption rates into the bloodstream. Vapors are simple molecules that exist in the gas phase at room temperature; they can cause inhalation issues in manufacturing processes that release hazardous molecular contamination. In high concentrations, toxic vapor can cause chemical burns or death. Many of the common organic solvents used in chemistry have vapors associated with them that can be harmful to the eyes and mucus membranes. Hydrogen chloride, for example, is a common laboratory reagent that is a vapor at room temperature; another, hydrogen bromide, is a fellow traveler.

Cornell University’s Environment, Health, and Safety laboratory manual, cites potential chemical inhalation symptoms including, “eye, nose, and throat irritation; coughing; difficulty breathing; headache; dizziness; confusion; and collapse.”¹

Unfortunately, vapors can be difficult to trap. Common powder filters will not stop them, and while charcoal filters can trap certain vapors, they are not 100% effective nor are they cost effective for large quantities of vapor loss. Furthermore, they can slowly release the trapped contaminant back into the environment. As a result, it is crucial to implement necessary testing, protection, and containment mechanisms to protect employees from these common vapor contaminants.

Determining Air Quality and Preserving a Safe Working Environment

To verify whether your air is safe and breathable for employees, you’ll need to implement detection methods that correspond with your process.

Powder detection is conducted via industrial hygiene monitoring systems that utilize small filters attached to pumps that draw in air. The filters capture any particulates that might be in the air to demonstrate exposure potential. Following contact, the filters are extracted and analyzed to determine quantity of hazardous material and concentration potential. Generally, these systems are designed to detect specific material that could be produced as a by-product of your process; as a result, you may miss other threats that your team didn’t know to test for.

When dealing with potent vapors, install monitors and sensors designed to detect the presence of gases likely to be associated with your manufacturing processes. Currently, there are highly sensitive sensors available that can report the presence of such materials in parts per million (PPM) using light absorption in the near infrared. There are also sensors which can detect low oxygen levels sometimes caused by inert vapors which have displaced breathable air from the room environment. Indirect measurement systems like a gas detector containing a vibrating tuning fork inside an air sampling chamber can detect heavy gases like sulfur hexafluoride (SF₆). If this heavy gas is present, the pitchfork will begin to vibrate at a lower frequency.

Using Containment Devices to Improve Worker (and Patient) Safety

In most laboratories and pharma production areas, several risk-reduction strategies have been used for years. Containment infrastructure (fume hoods, glove boxes, etc.) are good examples. Once a safe limit has been identified, a team can work with an experienced manufacturer to design containment structures that keep the environment within desired limits. Containment can also be used to protect the product from its environment, ensuring that it remains aseptic and protected from potential human contaminants, including bacteria and pathogens.

Vapor and powder containment require different types of equipment; fume hoods are designed to contain fumes and vapors, while powder booths and gloved enclosures serve as the primary containment methods for powders. Both types of containment use air flow as the main method of containment, but how the air is treated afterwards depends on whether the method is designed to police vapor or powder concentrations. Vapors are generally exhausted from the building, while powders are trapped using filter technology. In very critical environments, employees may wear personal protective equipment (PPE) for an added layer of security.

Build Infrastructure for Better Workplace Air

In general, manufacturers of containment equipment become frustrated with other research and manufacturing fields that do not take advantage of the same developed technologies. However, this reticence appears to be changing. As industry leaders search for resources and metrics to guide their workplace safety initiatives, they will find a lack of existing recommendations from regulatory authorities. In other instances, acknowledging hazards may be viewed as a hindrance to development.

Despite these headwinds, opting to prioritize employee protection and mitigate risks by inputting safety sensors and containment equipment will yield safer processes, more confident personnel, and ultimately, a better product. The lithium battery, food preparation, electronic chip, and construction material industries are already taking a closer look at the diverse containment products being developed to contain powders and vapors.

References

1. Cornell University. 7.4.1 Inhalation. Environment, Health, and Safety Laboratory Safety Manual. https://ehs.cornell.edu/research-safety/chemical-safety/laboratory-safety-manual/chapter-7-safe-chemical-use/74-routes-0