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A complete guide to storing hazardous chemicals safely and efficiently - Hazardous Substances Storage Guidelines


Chemical storage is a critical aspect of maintaining safety in any workplace that handles hazardous substances. Whether you work in a laboratory, industrial facility, or even a household setting, proper hazardous substances storage practices are essential for preventing accidents, protecting the environment, and complying with regulations. In this comprehensive guide, we’ll walk you through everything you need to know about safe and efficient hazardous substances storage.

In Thailand, the basic law to regulate chemical management is Hazardous Substance Act B.E. 2535 (1992). The act regulates manufacture, import, export and possession of hazardous substances.

General Storage Requirements

  • Documentation: Always review a chemical’s MSDS/SDS for proper hazardous substances storage procedures.
  • Location: Store chemicals in a dedicated, well-ventilated area away from sunlight, heat, and pathways. Limit access to authorized personnel.
  • Temperature Control: Maintain proper temperatures; refrigerate chemicals if needed. Never store food in lab refrigerators.
  • Labeling: Clearly label containers with chemical name, hazard classification, and safety info. Ensure labels are durable.
  • Container Integrity: Use undamaged containers made of compatible materials to prevent leaks.
  • Accessibility: Store chemicals for easy access while keeping aisles clear. Keep hazardous chemicals below eye level. Do not store chemicals on the floor, window ledges, or balconies.
  • Spill Containment: Have spill trays or absorbents available to contain spills. Use secondary containment like dishpans or polyethylene if possible. 
  • Emergency Equipment: Keep emergency gear like spill kits, fire extinguishers and eye wash stations accessible. Ensure that personnel are trained in their use and know the location of emergency equipment.
  • Regular Inspections: Regularly inspect storage areas for hazards, leaks, and damaged containers. Check all chemical containers left out of storage areas at the end of each workday and return unneeded items to chemical storerooms or stockrooms.
  • Inventory Management: Use a first-in, first-out system to avoid degradation. Keep containers closed when not in use.
  • Shelving: Use chemical-resistant shelving and avoid exceeding weight limits.
  • Personal Protective Equipment (PPE): Use appropriate PPE, including chemical-resistant gloves, eye protection, closed-toe shoes, lab coats, and chemical aprons as required.
  • Acid storage: Store acids in dedicated cabinets, with oxidizing acids isolated separately (i.e., each in its own separate secondary containment).

Segregating Hazardous Chemicals

Sort hazardous chemicals according to their compatibility and hazard classification to minimize the potential for dangerous reactions. Keep incompatible chemicals apart to prevent risks like fires, explosions, or the creation of toxic or flammable compounds. Avoid relying solely on alphabetical ordering unless chemicals are safe to store together or already grouped by hazard class.

Mishaps involving incompatible hazardous substances storage can lead to serious consequences, including fires, explosions, and the release of harmful substances. If storing incompatible chemicals together is unavoidable, ensure there’s physical separation, such as secondary containment measures, to mitigate risks.

Below is a guideline for storing hazardous chemicals according to compatibility:

The table showing the compatibility storage guidelines of chemical products.

Storage according to the chemical groups

When it comes to hazardous substances storage, one size does not fit all. Different types of chemicals have different properties and require specific storage conditions to remain stable and safe. 

Corrosive Chemicals

Inorganic Acids

Inorganic acids are highly corrosive substances that can cause severe burns upon contact with skin or eyes. Examples include hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3)

Storage recommendation:

  • Store in acid-resistant cabinets made of acid-resistant materials like polyethylene, or epoxy-coated steel or secondary containment trays to prevent leaks.
  • Keep away from reactive materials such as metals.
  • Store separately from bases and cyanides to avoid potential reactions.

Organic Acids

Organic acids, such as trichloroacetic acid, acetic acid and formic acid, also possess corrosive properties, although typically less severe than inorganic acids. 

Storage recommendation:

  • Store in acid-resistant cabinets made of acid-resistant materials like polyethylene, glass or epoxy-coated steel or secondary containment trays.
  • Keep away from reactive materials such as metals.
  • Store separately from bases and cyanides to avoid potential reactions.


Bases, or alkaline substances, are corrosive chemicals that can cause severe burns and tissue damage. Examples include sodium hydroxide (NaOH), ammonium hydroxide (NH4OH) and potassium hydroxide (KOH)

Storage recommendation:

  • Store in designated areas away from acids and other reactive substances.
  • Use chemical-resistant storage containers and secondary containment measures.
  • Ensure proper labeling and signage to indicate the presence of bases.

Explosive Chemicals

Explosive chemicals include substances like nitroglycerin, TNT, and peroxides. Improper storage or handling of explosives can lead to catastrophic accidents.

Storage recommendation:

  • Store in specialized explosion-proof cabinets or bunkers.
  • Keep away from all other chemicals, heat, sparks, open flame and heavily trafficked areas.
  • Follow strict regulations and guidelines for handling and storage.
  • Incompatible with flammable liquids, oxidizers, acids and bases

Flammable Chemicals

Flammable chemicals encompass a wide range of substances that can ignite and burn easily. These include ethanol, benzene, and acetone.

Storage Recommendations:

  • Store in cool, well-ventilated areas away from ignition sources.
  • Store in flammable storage cabinet (in excess of 10 GAL/ 37854.1 mL) within secondary containment
  • Use safety cans or cabinets designed for flammable liquids.
  • Avoid overcrowding storage areas to minimize the risk of spills and accidents.
  • Incompatible with oxidizers

Flammable Compressed Gases

Flammable compressed gases, such as propane, acetylene and butane, present a significant fire risk if not handled and stored properly.

Storage Recommendations:

  • Store in cool, dry and well-ventilated areas away from heat sources and ignition points.
  • Use secure strap or chain cylinders to a wall or bench top to prevent tipping or damage.
  • Ensure cylinders are properly labeled with their contents and hazards.
  • Incompatible with oxidizing and toxic compressed gases and oxidizing solids.

Oxidizing Compressed Gases

Oxidizing compressed gases, such as oxygen, bromine and chlorine, can intensify fires and support combustion. Proper storage is essential to prevent accidents.

Storage Recommendations:

  • Store in a cool, dry area, away from flammable and combustible liquids/gases.
  • Keep cylinders upright and secured to prevent damage.
  • Provide adequate ventilation to dissipate any released gases safely.
  • Securely strap or chain cylinders to a wall or bench top.

Oxidizing Chemicals

Oxidizing agents like sodium hypochlorite, potassium chlorate and nitrates readily donate oxygen or accept electrons during a chemical reaction, increasing the risk of fire or explosion.

Storage Recommendations:

  • Store separately from reducing agents, flammables, and combustibles.
  • Keep containers tightly sealed and store in secondary containment to prevent contamination.
  • Ensure compatibility with storage materials to prevent reactions.

Water-Reactive Chemicals

Water-reactive chemicals like sodium metal, potassium metal and lithium metal react violently with water or moisture, releasing heat, gas, or even igniting spontaneously. 

Storage Recommendations:

  • Store in dry, cool locations and airtight containers to prevent exposure to moisture.
  • Keep away from all water sources/ solution, humidity and oxidizers. 
  • Handle with extreme caution to avoid accidents.

Storage in Different Locations

The below are some common locations for hazardous substances storage.


Stockrooms serve as the primary storage area for chemicals in many facilities. Maintaining organization within stockrooms is crucial for efficiency and safety. Here’s how to ensure your stockroom is optimized for chemical storage:

  • Labeling: Properly label all containers with the chemical name, hazard symbols, and expiration date if applicable. Clear labeling reduces the risk of confusion and mishandling.
  • Segregation: Store chemicals based on compatibility to prevent reactions. Flammable liquids should be kept away from oxidizing agents, acids, and other reactive substances. Utilize separate shelves or cabinets for different chemical classes.
  • Ventilation: Ensure adequate ventilation in the stockroom to prevent the accumulation of fumes. Install exhaust systems or keep windows open to maintain air quality.
  • Spill Kits: Keep spill response kits readily available in the stockroom to address accidents promptly. These kits should contain absorbent materials, gloves, goggles, and neutralizing agents.


Shelves and cabinets offer convenient storage solutions for smaller quantities of chemicals or frequently used substances. Proper organization and maintenance are essential for safety:

  • Weight Capacity: Ensure shelves and cabinets are capable of supporting the weight of the chemicals stored on them. Overloading shelves can lead to collapse and spills.
  • Chemical Compatibility: Similar to stockrooms, segregate chemicals based on compatibility to prevent unintended reactions. Utilize spill containment trays or bins to contain spills and leaks.
  • Accessibility: Arrange chemicals in a logical order, with frequently used items easily accessible. Avoid overcrowding shelves to maintain visibility and access. Avoid storing all chemicals above shoulder height. Store large containers (1 gal / 37854.1mL or larger) and corrosive materials below eye level.
  • Regular Inspections: Conduct regular inspections of shelves and cabinets for signs of deterioration or leakage. Replace damaged or corroded shelves promptly to prevent accidents.

Flammable Materials Store Rooms

Flammable materials pose a significant fire risk if not stored correctly. Designated flammable materials store rooms provide the necessary containment and protection. Here’s how to manage flammable chemicals safely:

  • Fireproof Construction: Construct flammable materials store rooms with fire-resistant materials such as concrete or metal. Install fire-rated doors and automatic fire suppression systems for added safety.
  • Temperature Control: Maintain consistent temperatures within the store room to prevent overheating or ignition. Avoid exposure to direct sunlight or heat sources.
  • Grounding: Ground all containers and equipment to prevent static electricity buildup, which could ignite flammable vapors. Use bonding straps when transferring flammable liquids between containers.
  • No Smoking Policy: Enforce a strict no smoking policy within and around flammable materials store rooms. Post visible signs indicating the prohibition of open flames and smoking.

Chemicals required to store in flammable materials store rooms: 

  • Flammable Liquids (gasoline, acetone, ethanol, methanol, toluene, and various solvents)
  • Flammable Gases (propane, butane, methane, hydrogen, and acetylene)
  • Flammable Solids such as certain types of powders, finely divided metals like aluminum or magnesium, and certain chemical compounds.
  • Aerosols (pressurized containers containing flammable propellants for various products like spray paints, hairspray, or insecticides)


Refrigerators and freezers play a vital role in storing temperature-sensitive chemicals, reagents, and biological samples. Proper storage conditions are essential to maintain chemical stability and integrity:

  • Temperature Monitoring: Set and maintain appropriate temperature settings according to the requirements of the chemicals stored. Regularly monitor temperatures using built-in thermometers or external monitoring devices.
  • Segregation: Dedicate specific shelves or compartments for chemical storage to prevent cross-contamination with food items. Clearly label containers to avoid confusion.
  • Spillage Containment: Use sealed containers or secondary containment trays to prevent spills from leaking onto other stored items. Clean up spills promptly to avoid contamination and odors.
  • Inventory Management: Keep an updated inventory of chemicals stored in the refrigerator/freezer. Discard expired or deteriorated chemicals following proper disposal procedures. Defrost occasionally to prevent chemicals from becoming
    trapped in ice formations.
  • Emergency Backup: Install backup power systems or alarms to ensure temperature stability during power outages or equipment malfunctions. Have a contingency plan in place for transferring chemicals to alternative storage if necessary.

Chemicals required to store in Refrigerator/ Freezer: 

  • Biological samples (e.g., DNA, RNA, proteins)
  • Enzymes and other proteins
  • Antibiotics and antifungals
  • Growth factors and hormones
  • Certain pharmaceuticals (e.g., insulin)
  • Temperature-sensitive reagents (e.g., PCR master mixes)
  • Radioactive materials (in some cases, for short-term storage)
  • Certain volatile organic compounds (VOCs) that require low temperatures to maintain stability.

Secondary Containment

Secondary containment measures are essential for preventing chemical spills and leaks from reaching the environment. Implementing these measures adds an extra layer of protection and regulatory compliance:

  • Containment Basins: Store chemicals in secondary containment such as polyethylene or stainless steel trays to separate incompatible chemicals stored in the same area and capture spills and leaks. Choose materials compatible with the chemicals stored to prevent degradation or corrosion.
  • Leak Detection Systems: Install leak detection sensors or alarms to promptly identify and address leaks before they escalate. Regularly test and maintain these systems to ensure reliability.
  • Emergency Response Plan: Develop and train staff on an emergency response plan for chemical spills or leaks. Clearly outline procedures for containment, cleanup, and reporting to minimize environmental impact.
  • Regular Inspections: Conduct routine inspections of containment systems to check for damage, corrosion, or deterioration. Repair or replace damaged components as needed to maintain effectiveness.
  • Regulatory Compliance: Familiarize yourself with local regulations and requirements regarding secondary containment for chemical storage. Ensure compliance with applicable laws to avoid fines or penalties.

Chemicals required to store in Secondary Containment: 

  • Corrosive chemicals such as acids or bases
  • Flammable liquids or solvents
  • Toxic substances
  • Reactive chemicals that can undergo hazardous reactions if they come into contact with other substances

By incorporating these guidelines into your chemical storage practices, you’ll not only promote a culture of safety but also contribute to the overall efficiency and organization of your workplace. Remember, safety always comes first.