Closed vs Open Waste Containers: Exposure Comparison

The distinction between open and closed waste container systems in the lab is not just a design preference; it directly impacts exposure levels, fire risk, and inspection outcomes.

Open waste containers take many forms: uncapped bottles, containers loosely covered with parafilm, or bottles fitted with open funnels. In each case, inadequate sealing allows continuous volatilization of solvents and reagents into the surrounding air. Even chemicals with relatively low vapor pressure can accumulate over time, particularly in confined or poorly ventilated environments.

An open waste container placed in a fume hood canprotect the lab personnel, but it doesn't however, it does not contain the vapors themselves. These emissions are simply transferred into the exhaust system where they can contribute to environmental degredation and expose individuals in neighboring buildings.

In contrast, closed systems are engineered specifically to prevent vapor from escaping.

From an exposure and risk standpoint, the difference between open and closed systems is substantial. Open systems act as persistent emission sources, contributing to:

  • Chronic low-level inhalation exposure for nearby personnel
  • Elevated background VOC concentrations
  • Increased odor complaints and worker discomfort
  • Fire and explosion risk from accumulation of flammable vapors

Effective vapor containment relies on three core principles:

  • Physical sealing at all connection points (lid, tubing, fittings)
  • Controlled ingress of liquid waste without exposing the internal vapor space
  • Managed egress of gases through filtered, pressure balancing mechanisms

Containment is not solely about preventing spills-it is about controlling phase transfer. Many laboratory solvents (e.g., acetone, methanol, acetonitrile) readily transition to vapor at room temperature. Without proper containment, every waste container can become a passive emission source.

Closed systems contain liquid waste and vapors within a sealed pathway. This includes not only the container itself, but also how waste enters the container and how pressure is managed. The most common closed system features a solvent delivery port cap to feed chemicals through sealed tubing into lab equipment (E.g., HPLC & LC/MS machines.) Spent chemicals exit through sealed waste tubing into a vented waste collection port cap. The only vapor exchange in a closed system like this is filtered through controlled air inlet and outlet valves. All connectors are tightly secured, and no air can escape. This is an example of a perfect closed system.

Aside from automated processes, many labs also have human personnel routinely generating small amounts of liquid waste. When this is the case, a completely closed system is impractical because the process of continually un-capping, placing a funnel, pouring waste, and re-capping a container is sufficiently laborious and inconvenient to encourage personnel to cut corners and leave the waste container open... inviting regulatory fines, endangering the health of those nearby, and increasing the risk of fire in the lab. For these situations, ECO Funnel® is the ideal liquid waste collection device. It performs the same function as a closed system (preventing volatiles from escaping) while enabling a high adoption rate in the lab through ease of use.

An ECO Funnel forms an airtight seal on any waste container with matching threads. It's long tube is submerged in the waste, effectively reducing the surface area to 1/4 in2 and trapping the majority of fumes inside the waste container -even when the lid is open. Through its clever design, ECO Funnel prevent sexposure and minimizes fire risk similar to a fully closed system, while still allowing users to quickly and easily dispose of their waste.

While some regulators have stated that the original closure as the only way to completely seal a waste container, many others have agreed that a closed and latched ECO Funnel is sufficiently closed in between waste generation to meet their requirements, and have encouraged labs under their jurisdiction to expand their use of these essential safety devices.

Steve Carrol, retired San Diego Fire Marshal and Biotech Inspector, stated that he considered the ECO Funnel as the "ideal containment system that eliminates the danger of ignited vapors and spills from open chemical waste containers."

Explore our ECO Funnels and Port Cap Closed Systems