Safety and Storage

Part of Acids and Alkalis

Protocols for safely storing acids and alkalis, labeling systems, segregation rules, and container selection.

Why This Matters

Improper storage of acids and alkalis kills people. Unlabeled containers get mistaken for water or food. Acids stored next to alkalis react violently if containers fail. Lye stored in a thin wooden vessel absorbs moisture and degrades the container until it leaks. Acid stored in a metal bucket corrodes through silently until the floor is flooded with corrosive liquid.

These are not hypothetical concerns. In pre-industrial and early industrial chemistry, chemical accidents were the leading cause of death in workshops. Most were preventable with simple storage discipline. In a rebuilding community where medical care is limited and experienced chemists are rare and irreplaceable, the loss of even one person to a preventable accident is catastrophic.

Good storage habits also protect your chemical supplies. Lye left in an unsealed container absorbs moisture and carbon dioxide from the air, converting to sodium carbonate (washing soda) — still useful, but no longer usable for soap without adjustment. Vinegar stored in a loosely covered container evaporates and weakens. Proper storage means your chemicals are ready to use when you need them.

Container Selection by Chemical Type

For Acids (Vinegar, Fermented Acid Solutions)

Container	Suitability	Notes
Glass with tight cork or stopper	Excellent	Best choice; inert, impermeable, visible
Glazed ceramic with tight lid	Very good	Unglazed pottery is porous and may be attacked by acids
Dense hardwood barrel (sealed with wax)	Good for dilute acids	Not suitable for concentrated acids
Lead-lined wooden containers	Traditional for strong acids	Lead poisoning risk — avoid for food-related acid storage
Iron or steel	Poor	Iron corrodes rapidly in acid
Copper	Poor	Copper dissolves in acid, creating toxic copper salts
Unglazed clay	Poor	Too porous; acid seeps through

Preferred for dilute acid (vinegar, weak acid solutions): Sealed glass jars, glazed pottery crocks with fitted lids, or hardwood barrels with the interior sealed using hot beeswax.

For Alkalis (Lye Solutions, Wood Ash Solutions)

Container	Suitability	Notes
Glass with cork	Excellent	Preferred for small quantities
Glazed ceramic	Good	Must be free of cracks; lye attacks cracks and widens them
Hardwood sealed with pine resin	Good	Traditional soapmaker’s container
Iron	Acceptable for short-term	Iron is stable in lye but may contaminate solution
Lead	Poor	Lye corrodes lead
Copper	Very poor	Lye attacks copper rapidly
Aluminum (if salvaged)	Never	Lye reacts violently with aluminum, generating hydrogen gas

Aluminum and lye

Never store or mix lye with aluminum containers, tools, or surfaces. The reaction produces hydrogen gas (flammable and explosive) and can cause violent boiling. Even a small amount of aluminum contamination is dangerous.

For Dry Lye (Potash or Soda Ash)

Dry lye absorbs moisture from the air and carbon dioxide, gradually converting to less useful carbonate forms. Store:

• In sealed glass jars or ceramic crocks with tight-fitting lids
• With a small amount of wood shavings or charcoal inside the container to absorb moisture (change regularly)
• In a cool, dry location away from steam and cooking fires
• In small batches — open containers only as needed, reseal immediately

Labeling System

Every chemical container must be labeled. In a literate community, written labels with standardized symbols are sufficient. In a community with mixed literacy, add a physical marker system.

Minimum Label Information

1. Name of substance (e.g., “Strong Lye,” “Wood Ash Vinegar,” “Sulfuric Acid”)
2. Strength/concentration (e.g., “Strong — soapmaking grade,” “Dilute — safe for food use”)
3. Date made or obtained
4. Hazard level (see below)

Hazard Symbol System

Use a simple carving, stamp, or paint mark system that anyone can learn:

Symbol	Meaning
Single scratch mark	Mildly hazardous — dilute acid or dilute alkali
Double scratch mark	Moderately hazardous — strong vinegar, concentrated wood ash lye
Triple scratch mark + skull/warning mark	Highly hazardous — concentrated acid or strong lye
X mark	Unknown — do not use until identified

Standardize these symbols across your community and teach them to everyone who might enter the storage area, including children.

Segregation Rules

The most important storage safety rule: acids and alkalis must never be stored in the same location or near each other.

If containers fail simultaneously (earthquake, flood, shelf collapse), acid and alkali mixing can:

• Produce violent heat and spattering
• Generate toxic gases (if the acid is concentrated)
• Cause rapid, uncontrolled chemical reactions in an uncontrolled environment

Segregation Layout

Designate separate storage zones with clear physical separation:

• Acid storage area: One end or corner of the building, low shelving, well-ventilated
• Alkali storage area: Opposite end, equally low, well-ventilated
• Neutral/unclassified chemicals: Middle ground or separate room
• Buffer zone: At least 2 meters of clear floor between acid and alkali zones

Mark zones visibly with paint, carved markers, or hung signs.

Shelf and Storage Furniture

Low Shelving

Store heavy containers at floor level or on low shelves, not high up. A heavy glass jug of lye falling from a high shelf is a serious accident even before it breaks; breaking on impact converts it into a chemical exposure emergency.

Maximum recommended height for heavy corrosive containers: waist height (approximately 1 meter).

Secondary Containment

Place all acid and alkali storage containers inside a secondary container (called a berm or drip tray) that can hold the full volume of the primary container if it leaks or breaks.

Construction:

• Pottery basin or tray with raised sides
• Sealed wooden tray with waxed interior
• Clay-lined pit beneath shelving

If the primary container fails, the secondary containment captures the spill before it reaches the floor, other chemicals, or people.

Ventilation

Storage areas must be ventilated. Acid containers release small amounts of vapor; lye solutions release ammonia-like odors if they have reacted with nitrogen-containing compounds. A window or vent opening near the top of the storage area (where vapors accumulate) is essential.

Do not store chemicals in an unventilated cellar unless you open and air it before entering.

Inspection and Maintenance Schedule

Establish a regular inspection routine — weekly for actively used chemicals, monthly for long-term stored chemicals.

Inspection checklist:

• All containers sealed and undamaged
• Labels present and readable
• No visible corrosion, staining, or crystalline deposits on container exteriors
• No odor of acid or ammonia beyond a background level
• Secondary containment trays clean and intact
• Segregation zones maintained — no mixing of acid and alkali storage

When to discard:

• Any container that shows cracks, pitting, or significant corrosion
• Any chemical that has changed color, consistency, or odor unexpectedly
• Any container with a damaged or missing label (re-label only if you are certain of the contents; discard if uncertain)

Emergency Procedures

Post these visibly in or near the storage area:

1. For a spill: Do not touch. Alert others. Ventilate the area. Refer to Spill Response protocols.
2. For skin contact: Immediately flush with large volumes of clean water for 15 minutes. Do not apply any neutralizing agent (vinegar, baking soda) — plain water is the correct treatment.
3. For eye contact: Immediately flush with clean water continuously for 20 minutes. This is a medical emergency — seek all available help.
4. If in doubt about a container’s contents: Do not open. Treat as highly hazardous until identified.

Keep a 20-liter bucket of clean water permanently in the storage area as emergency rinse supply. Replenish it whenever it is used.