Chemicals with an inhalation hazard, including gases, vapors, aerosols, dusts, and fine mists, must be handled with precise location controls to prevent respiratory exposure. These airborne materials can bypass the body’s natural defenses and be absorbed into the bloodstream, leading to irritation, systemic toxicity, or long-term damage to the lungs and other organs. The physical location where these substances are used and stored acts as a primary barrier against immediate and chronic health risks. Establishing strict protocols for the handling location is essential for protecting personnel who interact with these dangerous materials.
Requirements for Active Handling and Use Areas
The moment a chemical with an inhalation hazard is opened or manipulated, it must be contained within a dedicated Local Exhaust Ventilation (LEV) system. The most common and effective equipment for this purpose is a certified chemical fume hood. Fume hoods operate by drawing air across the work surface and away from the user, capturing and exhausting airborne contaminants before they can reach the breathing zone.
The entire room housing the fume hood should be maintained at a negative pressure relative to surrounding, non-laboratory spaces, such as hallways or offices. This pressure differential ensures that air always flows into the hazardous area when doors are opened, preventing the escape of vapors or gases to cleaner areas. For the fume hood to function properly, the air velocity at the hood face—the sash opening—must be maintained within a narrow range, typically between 100 and 150 linear feet per minute (LFM). Maintaining the sash at the lowest possible working height optimizes the capture velocity and provides a physical barrier between the user and the chemical operation.
The selection of a fume hood depends on the chemical’s properties; highly volatile or toxic materials require rigorous monitoring and specific hood types. Other forms of LEV, such as snorkel exhausts or slotted benches, may be appropriate for specialized tasks that generate small amounts of vapor or dust. However, these localized capture devices are not substitutes for a full fume hood when handling large volumes of volatile liquids or highly hazardous substances. The use area must be equipped with engineering controls designed to remove the contaminant at its source, rather than simply diluting it within the room air.
Secure Locations for Chemical Storage
When not in active use, chemicals posing an inhalation hazard require storage in specific environments to maintain their stability and prevent accidental release. The storage location must control environmental factors like temperature and light exposure, as excessive heat or direct sunlight can increase the chemical’s volatility and the rate of vapor generation. Dedicated, appropriately rated storage cabinets or rooms are mandated for these materials.
Storage segregation is an important consideration, ensuring that chemicals are grouped by hazard class rather than alphabetically to prevent dangerous, incompatible reactions. Inhalation hazards must be physically separated from materials like oxidizers, which could accelerate a fire, or corrosives, which could breach a container and release a toxic gas. For chemicals that are also flammable, specialized fire-rated cabinets are necessary, typically constructed with a double-wall and air space for insulation against fire.
These storage cabinets must feature a liquid-tight spill sump at the bottom, designed to contain any leaks or spills from the stored containers. While venting is not universally required for all cabinets, mechanical ventilation systems are often necessary in storage rooms to prevent the accumulation of low-level vapors that could exceed safe exposure limits or create an explosive atmosphere. The overall storage area must also be kept clear of clutter and unauthorized materials to allow for quick access and safe spill response.
Essential Facility Safety Infrastructure
The physical environment surrounding both the active use and storage locations requires fixed safety features to mitigate accidental exposure. The entire area must be clearly demarcated and access restricted solely to authorized, trained personnel. Highly visible warning signs are necessary, incorporating Globally Harmonized System (GHS) pictograms that instantly communicate the chemical’s inhalation hazard.
Within the immediate work area, emergency equipment must be instantly accessible in the event of a splash or spill exposure. Safety showers and eyewash stations are required wherever employees may be exposed to injurious corrosive materials. These devices must be located within a 10-second travel time, approximately 55 feet, from the hazard, and must deliver a continuous flow of tepid water for a full 15 minutes. Work surfaces and flooring in handling areas should be non-porous and easy to decontaminate, and liquid chemicals should be placed in secondary containment trays during dispensing to manage potential leaks.
Regulatory Context and Communication Tools
The determination of where an inhalation hazard chemical should be stored or used is codified by regulatory requirements designed to protect the worker. In the United States, chemical safety in the workplace is largely governed by the Occupational Safety and Health Administration (OSHA), particularly the Hazard Communication Standard. This standard mandates that employees be informed about the hazards they face and the protective measures required.
The Safety Data Sheet (SDS) for each chemical is the definitive tool that specifies the substance’s hazards, required engineering controls, and recommended storage conditions. Section 7 of the SDS, which covers handling and storage, directly informs the proper physical location and environment for the material. Additionally, GHS labels affixed to containers use standardized pictograms and signal words to communicate the severity of the inhalation risk. These standardized communication tools ensure that required safety procedures and locations are consistently applied across different workplaces.