Chemical precautions are the specific safety measures you take to protect yourself and others from harm when handling, storing, or working near hazardous substances. These precautions fall into several categories: understanding the hazard, wearing the right protective equipment, controlling exposure through ventilation and containment, storing chemicals properly, and knowing what to do if something goes wrong.
Identify the Hazard First
Every chemical precaution starts with knowing what you’re dealing with. Chemicals are classified into hazard categories, each represented by a standardized pictogram you’ll find on labels and Safety Data Sheets (SDS). A flame symbol means the substance is flammable or can self-heat. A skull and crossbones signals acute toxicity, meaning the chemical can be fatal or toxic from a single exposure. A corrosion symbol warns of skin burns, eye damage, or the ability to eat through metals. An exclamation mark indicates a lower-level irritant or sensitizer.
Less obvious but equally important are the health hazard pictogram, which flags long-term dangers like cancer risk, reproductive harm, or organ damage, and the oxidizer symbol (a flame over a circle), which marks chemicals that can intensify fires by supplying oxygen. Compressed gases, explosives, and chemicals toxic to aquatic life each have their own symbols as well.
The Safety Data Sheet is your most detailed resource. Every chemical product is required to have one, and it contains 16 standardized sections covering everything from first aid measures and firefighting instructions to safe handling, storage conditions, and exposure limits. Section 7 specifically lists precautions for safe handling. Section 8 tells you exactly what personal protective equipment to use. If you’re unsure how to handle any chemical, the SDS is the first document to read.
Wear the Right Protective Equipment
Personal protective equipment (PPE) is your last line of defense when engineering controls aren’t enough to eliminate exposure. The basics include gloves, eye protection, a lab coat or chemical-resistant clothing, and sometimes respiratory protection. But “wear gloves” is too vague to be useful. The type of glove matters enormously, because different materials resist different chemicals.
Butyl rubber gloves offer the broadest chemical resistance. They provide excellent protection against solvents like benzene, chloroform, toluene, and xylene, often lasting more than eight hours before any chemical passes through. They also have the highest resistance to gas and water vapor permeation, making them a strong choice when handling toxic substances. Nitrile gloves work well for alcohols like ethanol and methanol, formaldehyde solutions, and hydrochloric acid, but they break down quickly when exposed to aromatic solvents. For chlorinated and aromatic solvents specifically, Viton gloves are considered excellent.
The wrong glove material can dissolve or allow chemicals to pass through to your skin within minutes. Always check the SDS or a chemical resistance chart before selecting gloves. Eye protection should be splash-proof chemical goggles rather than standard safety glasses whenever there’s a risk of liquid splashing. A face shield adds protection but doesn’t replace goggles.
Control Exposure With Ventilation
The safest approach is preventing chemical vapors and fumes from reaching you in the first place. A fume hood is the primary engineering control in laboratories. It draws air away from you and vents it safely, creating a barrier between you and hazardous vapors. For a fume hood to work properly, air must flow into it at a minimum speed of 80 feet per minute across the face opening. Working with the sash (the glass panel) pulled down as far as possible increases this protective airflow.
In industrial settings, local exhaust ventilation serves the same purpose by capturing fumes at the source. General room ventilation helps but is not a substitute for local exhaust when working with volatile or toxic chemicals. If adequate ventilation isn’t available, respiratory protection becomes necessary, and the type of respirator depends on the specific chemical and its concentration in the air.
Store Chemicals by Compatibility
Improper storage causes fires, explosions, and toxic gas releases. The core rule is to separate chemicals by compatibility group, not alphabetically. Chemicals that react dangerously with each other must never share shelf space. The major groups that require separation are flammable liquids, compressed gases, volatile poisons, acids, liquid bases, liquid oxidizers, non-volatile liquid poisons, and air- or water-reactive materials like metal hydrides.
Acids deserve special attention because they’re involved in some of the most dangerous storage mistakes. Oxidizing acids (sulfuric, nitric, chromic, perchloric) must be stored away from organic acids (acetic, formic, propionic). Oxidizing acids are highly reactive with most substances and should be double-contained, meaning the primary bottle sits inside a non-corrosive tray or tub. Perchloric acid is particularly hazardous and must be carefully isolated from alcohol, paper, wood, oil, ether, grease, and especially acetic acid.
Acids should also be kept away from cyanide salts and metal sulfides, which release poisonous gas on contact. As a general rule, store dry solids above liquids on shelves. If a liquid container breaks, you don’t want it dripping onto reactive powders below. This is especially critical when cyanide- or sulfide-containing solids are stored nearby, since even water spilling onto them can produce toxic gas.
Handle Chemicals Safely
Beyond PPE and ventilation, everyday handling practices prevent most chemical incidents. Keep containers closed when not actively pouring or dispensing. Never use your mouth to pipette. Label every container, including secondary containers you’ve transferred chemicals into. Work in well-lit, uncluttered spaces where you can see what you’re doing and move freely.
Employers who have hazardous chemicals in the workplace are required by OSHA’s Hazard Communication Standard to label all containers, maintain Safety Data Sheets for every product, and train workers on how to handle chemicals appropriately. This includes training on how to read labels and SDS documents. If you work with chemicals and haven’t received this training, you’re entitled to it.
Know What to Do in an Emergency
Chemical spills and exposures happen even with precautions in place. Knowing the response before an incident occurs is itself a precaution.
If you’re exposed to a chemical release, the CDC recommends three immediate steps: get away from the area, get the chemical off your body, and get help. If the release is indoors, move outside to fresh air. If it’s outdoors, move upwind and as far away as possible. Remove contaminated clothing and shower as quickly as you can, ideally within the first 10 minutes. If you can’t shower, wipe off as much of the chemical as possible. Then call Poison Control at 800-222-1222, call 911, or go to the nearest hospital.
For eye exposure, emergency eyewash stations should deliver flushing fluid for a full 15 minutes at a minimum flow rate of 0.4 gallons per minute. That’s a long time, and people often stop too early. Fifteen minutes of continuous flushing is the standard set by ANSI, and cutting it short can result in ongoing chemical burns.
A well-stocked chemical spill kit should be within reach anywhere chemicals are used. Essential contents include chemical-resistant gloves, a face shield, absorbent pads and socks, acid and base neutralizers, drain stoppers, tongs for broken glass, a hard-walled sharps container, polyethylene bags for waste, and caution signs to keep others away from the area. Labs that use mercury should also keep amalgamation powder on hand. Every spill kit should include a written cleanup protocol so you’re not relying on memory during a stressful moment.