05 Aug Empty Containers Can Still Be Dangerous

Empty Containers Can Still Be Dangerous

An empty container is not necessarily a safe container. Drums, tanks, cans, pails, and other containers that previously held flammable or combustible liquids may still contain enough residual liquid or vapor to create a serious fire or explosion hazard.

After the liquid has been removed, flammable vapors may remain and mix with air inside the container. If that vapor-air mixture is within its flammable range, a spark, flame, or other ignition source can cause an explosion.

Guide for Discussion

Treat Empty Containers as Hazardous

Unless a container has been properly cleaned, tested, and determined safe:

• Assume hazardous residues or vapors remain inside.
• Keep the container closed when it is not being used.
• Keep it away from flames, sparks, hot surfaces, and other ignition sources.
• Do not smoke near the container.
• Do not cut, weld, braze, solder, grind, drill, or perform other hot work on it.
• Do not use empty drums or pails as welding tables, cutting stands, workbenches, or supports for grinding operations.
• Follow the container label, Safety Data Sheet (SDS), and company procedures for handling and disposal.

A container that looks clean or smells empty may still contain hazardous concentrations of vapor.

Hot Work on Containers

Hot work involving a container that has held a flammable, combustible, toxic, or otherwise hazardous substance requires special precautions. Welding or cutting can heat residual material, release hazardous gases, or ignite vapors trapped inside the container.

Never perform hot work on a used container until it has been properly prepared and authorized in accordance with company hot-work procedures.

Preparation may require:

• Identifying the container’s previous contents.
• Reviewing the applicable SDS and hazards.
• Completely draining and removing residual material.
• Cleaning or purging the container using an approved procedure appropriate for the material involved.
• Testing the atmosphere with properly calibrated instruments when required.
• Verifying that oxygen and flammable-vapor concentrations are within acceptable limits.
• Testing for toxic contaminants when applicable.
• Providing adequate ventilation.
• Isolating connected piping, valves, or other sources that could introduce hazardous material.
• Completing the required hot-work permit and fire-prevention precautions.
• Continuing atmospheric monitoring when conditions could change.

Cleaning alone does not prove that a container is safe for hot work. The condition must be verified before work begins.

Do Not Improvise Cleaning or Inerting

Cleaning methods must be appropriate for the substance previously contained. Workers should not automatically use steam, caustic solutions, solvents, water, or other cleaning agents without an approved procedure because incompatible materials can create additional hazards.

Likewise, introducing nitrogen, carbon dioxide, or another inert gas should only be performed under an established procedure by personnel who understand the hazards. Inert gases can create an oxygen-deficient atmosphere and present a serious asphyxiation hazard.

Never enter a tank, vessel, drum, or other container unless the applicable confined-space requirements have been evaluated and followed.

Control Ignition Sources

Flammable vapors can escape from a container and travel to an ignition source some distance away. Ignition sources may include:

• Welding and cutting operations
• Grinding sparks
• Electrical equipment
• Static electricity
• Open flames
• Smoking materials
• Hot surfaces
• Internal combustion engines

Control ignition sources throughout the area—not just immediately next to the container.

Handling Empty Containers

Containers that previously held hazardous materials should be handled according to the product manufacturer’s instructions, SDS, company procedures, and applicable disposal or recycling requirements.

Do not reuse a container for another substance unless it has been properly cleaned, evaluated, and approved for that purpose. Never use an empty hazardous-material drum or container for drinking water, food, trash burning, seating, or an improvised work surface.

Remember

Empty does not mean safe. A container may have no visible liquid and still contain enough flammable vapor or hazardous residue to cause a fire, explosion, or harmful exposure.

Never weld, cut, grind, drill, or perform other hot work on a used container unless it has been properly cleaned, evaluated, tested, and authorized for the work.