Chemical safety is necessary for everyone who interacts with chemicals, whether in a professional laboratory, an industrial setting, or a home environment. Handling hazardous substances safely involves a sequence of structured steps designed to prevent exposure, injury, or property damage. This process starts with knowledge, as understanding the risks involved guides every subsequent safety decision. This approach ensures that all potential hazards are accounted for and mitigated before a chemical container is opened.
Understanding Hazard Information
The first step in handling any chemical is to acquire and understand its hazard information. This knowledge acquisition determines the necessary protective measures and emergency procedures for the substance. Two primary sources provide this information: the container label and the Safety Data Sheet (SDS).
The container label provides an immediate, visual summary of the hazards, following the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Key elements include one of two signal words: “Danger,” indicating a more severe hazard, or “Warning,” for a less severe one. Pictograms are standardized red-bordered diamonds containing a black graphic that visually communicate the type of risk, such as a flame for flammables or a skull and crossbones for acute toxicity.
For a detailed understanding, the Safety Data Sheet (SDS), formerly known as the Material Safety Data Sheet (MSDS), must be consulted. This standardized, 16-section document provides comprehensive information, including hazard identification, exposure controls, and proper handling and storage. Reviewing the SDS dictates everything from the required ventilation to the specific type of gloves needed.
Pre-Handling Preparation
Once the hazard information is understood, the next step is the physical preparation of the environment and the individual, focusing on engineering controls and personal protection. This preparation acts as a barrier between the user and the chemical.
The appropriate Personal Protective Equipment (PPE) selection is determined directly from the SDS, particularly the glove material, which must be chemically compatible with the substance. For instance, Nitrile gloves offer good general resistance to oils and many solvents. Butyl rubber is often required for strong acids and ketones because of its superior resistance to permeation.
Workspace preparation involves ensuring adequate ventilation is in place to control airborne contaminants. If a chemical has significant inhalation hazards, it must be handled inside a fume hood. A properly functioning fume hood maintains a specific air intake speed, known as the face velocity, typically ranging between 80 and 120 feet per minute (fpm). This airflow draws vapors away from the user, though excessive velocity can cause turbulence that may pull fumes back toward the opening.
Implementing Safe Use Techniques
With the environment and the individual prepared, the focus shifts to minimizing exposure during the active use of the chemical through controlled techniques. Working deliberately and slowly helps prevent sudden splashes or spills.
When transferring liquids, especially corrosives or large volumes, appropriate equipment like pumps or funnels should be used instead of free pouring. If pouring is necessary, the transfer must be done below eye level to reduce the risk of a splash reaching the face or eyes. When diluting strong acids, the general rule is to always add the acid slowly to the water, never the reverse, to control the heat generated by the reaction.
Any time a chemical is moved into a smaller, secondary vessel, that new container must be labeled immediately. This secondary label must include the product identifier and a clear indication of the hazards, often communicated through pictograms and the signal word. Only the minimal amount of chemical required for the task should be used, which limits the potential severity of any accidental release.
Post-Use Management
After the task is finished, safe handling concludes with securing the chemical, managing waste, and ensuring emergency readiness. Proper storage involves segregating chemicals based on their hazard class to prevent dangerous reactions if containers leak or break.
Incompatible chemical families, such as acids and bases, must be stored physically apart, often in separate storage cabinets. Flammable materials must be separated from oxidizers, as contact between these groups can lead to fire or explosion. Using secondary containment trays can contain a leak and prevent accidental mixing if a primary container fails.
Emergency equipment must be accessible and ready for immediate use. In the event of a chemical splash to the eyes or skin, the affected area must be flushed immediately at an eyewash station or safety shower for a minimum of 15 minutes. For spills, the initial response is to contain the material, using absorbent socks or barriers to stop the spread, before using an appropriate material to absorb the chemical for disposal.