Lead acid batteries can cause serious injury if not handled correctly. They are capable of delivering an electric charge at a very high rate. Gases released when batteries are charging – hydrogen (very flammable and easily ignited) and oxygen (supports combustion) – can result in an explosion.
The acid used as an electrolyte in batteries is also very corrosive and can cause injuries if it comes into contact with workers.
Electrolyte that has been spilled can also cause significant damage to property and the environment.
Hazards of working with batteries may include:
- electrolyte (acid) being splashed/spilled onto the body (including eyes)
- an explosion due to ignition of gases both inside and outside the battery.
Risk control measures
Safe handling and storage
- store batteries in a cool, well-ventilated area away from ignition sources (e.g. welding, smoking)
- avoid contact with internal components if the battery case is broken
- not handle batteries near heat, sparks or open flames
- protect containers from physical damage to avoid leaks and spills
- place cardboard or a spill tray between layers of stacked batteries to avoid damage and short circuits
- strictly follow all instructions and diagrams when installing or maintaining battery systems
- not allow conductive material to touch battery terminals
- a dangerous short-circuit may occur and cause battery failure and fire
- if installed batteries are at risk of metal tools or other conductive materials touching terminals, then the terminals should be insulated
- not place tools or cables on batteries or in an area where they can fall onto the terminals
- only use insulated tools
- not wear items of jewellery (e.g. watches, rings) as they may short out the terminals
- make sure correct battery terminals are used
- use an appropriate strap or cradle to carry batteries
- never carry them by their terminal posts.
Refer to the manufacturer’s instructions, including the Safety Data Sheet for additional information.
When working with acid electrolyte you should:
- ensure neutralising solutions are available for immediate use
- add concentrated acid slowly and carefully to the water (adding water to acid causes violent heat generation)
- stir the mixture with a glass or plastic (teflon) rod
- ensure stored electrolyte is decanted into an appropriate container e.g. glass, polyethylene or polypropylene container or a poly-lined drum
- not allow other metal (except battery terminals) to come into contact with acid or electrolyte
- allow the electrolyte to cool before checking its specific gravity
- allow the electrolyte to cool before filling batteries.
Before working with an electrolyte solution, ensure you have access to (and have read) the appropriate Safety Data Sheet (SDS).
In the case of a spill, follow the SDS instructions for electrolyte spill containment, clean-up and disposal details.
If electrolyte is spilled you should:
- shower in water, fully clothed, if electrolyte comes into contact with any part of the body or contact is suspected
- contain the spill with sand, earth or vermiculite
- remove the earth or sand once it has soaked up the acid/electrolyte
- wash the area to neutralise/decontaminate residue according to SDS for particular substance
- safely dispose of any contaminated material
- wear protective clothing, safety glasses, dust mask and gloves during clean-up of spills
When charging, you should:
- avoid excessive charging which electrolyses some of the water, emitting hydrogen and oxygen (outgassing)
- charge in a well-ventilated area
- ensure appropriate charging regimes for different types of batteries: flooded, Gel and AGM (Absorbed Glass Matt)
- check battery manufacturer’s specifications for recommended charging voltage thresholds
- regularly charge batteries to prevent sulfation
- not store batteries in a low charged condition
- always fully submerge plates of flooded batteries in electrolyte
- never add electrolyte during charging
- check the water level and fill to the designated level before charging, and top up after charging if necessary
- fill batteries with distilled or de-ionised water
- look out for the formation of gas bubbles in a flooded lead-acid cell
- this will indicate that the battery is reaching full state-of-charge (hydrogen on negative plate and oxygen on positive plate)
- reduce float charge if the ambient temperature is higher than 29°C (85°F)
- not allow batteries to freeze
- an empty battery freezes sooner than one that is fully charged
- never charge a frozen battery
- not charge at temperatures above 49°C (120°F).
Information, instruction and training
Workers should be informed, instructed and trained in:
- carrying out all maintenance recommended by the battery manufacturer, including checking and maintaining electrolyte levels in batteries where applicable
- selecting the appropriate replacement batteries to ensure the battery technology matches the workplace electrical charging system
- avoidance of ignition sources (e.g. sparks, flame) when working near batteries
- regularly checking the condition of the battery for physical damage or deterioration
- dealing with battery damage should acid leakage occur or explode the battery
- wearing of appropriate Personal Protective Equipment (PPE)
- first aid facilities and equipment
- safe hazardous manual task techniques.
Personal protective equipment
Workers must wear:
- PPE when handling or using batteries or the electrolyte (acid)
- rubber gloves and overalls, or apron protective equipment, if the battery is cracked or otherwise damaged
- safety goggles or a face shield when working on or charging batteries
- safety footwear
- a respirator during reclaim operations if the exposure limit for the hazardous gases/materials has been exceeded (refer to SDS for specific electrolyte)
- protective clothing, safety glasses, dust mask and gloves during clean-up of spills.
Consult the SDS for the electrolyte (acid) to determine the correct type of PPE.