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Lead acid batteries

Safety Alert
3 March 2015

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)
  • if the battery case is broken, avoid contact with internal components
  • do 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
  • do 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
  • tools or cables should not be placed on batteries or in an area where they can fall onto the terminals
  • only insulated tools should be used
  • when working on batteries, workers must 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.

Acid electrolyte

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
  • do 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.

Electrolyte spill

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

Safe charging

  • avoid excessive charging which electrolyses some of the water, emitting hydrogen and oxygen (outgassing)
  • charge batteries 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
  • do not store batteries in a low charged condition
  • plates of flooded batteries must always be fully submerged 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
  • formation of gas bubbles in a flooded lead-acid cell indicates 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)
  • do not allow batteries to freeze. An empty battery freezes sooner than one that is fully charged.
  • never charge a frozen battery
  • do 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

  • ensure PPE is supplied and worn when handling or using batteries or the electrolyte (acid)
  • consult the SDS for the electrolyte (acid) to determine the correct type of PPE
  • rubber gloves and overalls, or apron protective equipment, must be worn if the battery is cracked or otherwise damaged
  • safety goggles or a face shield should be worn when working on or charging batteries
  • wear safety footwear
  • a respirator should be worn during reclaim operations if the exposure limit for the hazardous gases/materials has been exceeded (refer to SDS for specific electrolyte)
  • wear protective clothing, safety glasses, dust mask and gloves during clean-up of spills.

Additional information and licence requirements

Refer to Part 9 of the Dangerous Substances Regulations 2002 (SA) and the Australian Code for the Transport of Dangerous Goods by Road and Rail for further information on licence requirements for the storage of batteries.

Refer to the manufacturer’s instructions, including the Safety Data Sheet.

Disclaimer: While care has been taken to ensure the accuracy and currency of the information in this publication, at the time of reading it may not be sufficiently accurate, current or complete to suit your individual needs. Reliance on the information in this publication is at your own risk. SafeWork SA accepts no liability for any loss resulting from your reliance on it. To best meet your work health and safety obligations refer to current Acts, Regulations and Approved Codes of Practice.