Quick lime has been handled on building sites and in works for thousands of years, and it has been burning people for just as long. It is not a toxic material in the usual sense; it is a reactive one. It reacts with water — including the water in skin, eyes and lungs — and the reaction gives off heat and makes a strongly alkaline hydroxide. Everything about handling it safely follows from that one fact.
This article is written for the people who receive, store, move and use quick lime and quick lime powder: the yard, the store, the slaker crew, the spreading gang. It is general guidance, not a substitute for the safety data sheet, the site's own risk assessment or training. The supplier's safety data sheet for the specific product is the document to work from.
The hazards, plainly
- Eyes. Lime dust or a splash of milk of lime in the eye causes serious damage, quickly, because the alkali keeps reacting with the tissue. This is the injury that matters most and the one every control is built around.
- Skin. Dry lime on dry skin is an irritant. Lime on wet or sweating skin, or inside a glove or a boot, slakes with the moisture and causes an alkali burn that is often not felt until it is deep.
- Breathing. Lime dust irritates the nose, throat and lungs; powders and fines produce it on every transfer.
- Heat. Quick lime in contact with water heats up fast. A wet bag, a leaking roof over a stockpile, a tanker washed out with lime still inside — each can get hot enough to damage packaging, and the steam carries lime with it.
- Swelling. Lime that hydrates in a closed container or a silo expands; bags split, and a silo that has taken water can become a serious problem.
Hydrated lime shares the eye, skin and dust hazards, without the heat.
Storage
- Dry, covered, off the ground, away from water lines, drains and anything that can leak. The store is the first safety control, not only a quality one.
- Keep quick lime away from acids and from materials that must not get hot.
- Keep bags closed until used. Rotate stock. A split or swollen bag is a sign that water has got in; handle it as a hazard, not a nuisance.
- Mark the store, and keep people who have no business there out of it.
Unloading and transfer
- Tipping lump lime makes dust; so does breaking a jumbo bag or emptying a sack. Tip downwind of people, wet nothing, and keep the drop height low.
- Lift jumbo bags by all their loops with equipment rated for the load; a bag that bursts a metre up puts a tonne of lime where people are standing.
- Pneumatic transfer from a tanker into a silo needs the silo vent filter working and the connections checked; lime blown out of a vent is a dust cloud over the yard.
- Do not wash down lime with a hose while anyone is close; water on a lime spill makes heat and alkali slurry. Sweep or vacuum dry material first.
Protective equipment
The minimum for anyone handling quick lime or working where its dust is present:
- Eye protection — sealed goggles, not open safety spectacles, wherever dust or splash is possible. A face shield as well when slaking or handling slurry.
- Gloves — alkali-resistant, long enough to cover the wrist, and worn so that lime cannot get inside; a glove full of lime and sweat is a burn.
- Clothing — long sleeves and trousers, cuffs closed, boots that lime cannot fall into. Contaminated clothing comes off and is washed; lime kept against the skin under clothing is a slow burn.
- Respiratory protection — a particulate respirator suitable for alkaline dust where dust cannot be controlled at source.
And the one item that is not personal equipment: an eye-wash station within a few seconds' reach of every place lime is handled, checked and full.
If lime gets on someone
- Eyes: flush immediately with clean water, holding the lids open, and keep flushing for a long time — the alkali keeps reacting and only water removes it. Get medical attention at once, continuing to flush on the way.
- Skin: brush off dry lime before wetting, then wash with plenty of water. Remove contaminated clothing. Get medical attention for any burn.
- Breathing: move to fresh air. Get medical attention if irritation persists.
- Swallowed: rinse the mouth, do not induce vomiting, get medical attention.
The safety data sheet gives the first-aid measures for the specific product; post them beside the eye-wash station.
What to ask the supplier for
A supplier of industrial lime should provide, without being pressed, a safety data sheet for each product — the hazard classification, handling, storage, first-aid and disposal information for that material — and packing that keeps the material contained in transit. Deshwali Minerals supplies safety and handling information with the order; the quality page describes how material is tested and released, and the packaging page shows the packing formats. Request a callback if your site needs the documentation before the first delivery.
Sources
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