(See BU-705: How to Recycle Batteries) The sulfuric acid in a lead acid battery is highly corrosive and is more harmful than acids used in most other battery systems. Contact with eye can cause permanent blindness; swallowing damages internal organs that can lead to death.
Other gases that can develop during charging and the operations of lead acid batteries are arsine (arsenic hydride, AsH 3) and (antimony hydride, SbH 3). Although the levels of these metal hydrides stay well below the occupational exposure limits, they are a reminder to provide adequate ventilation.
The blood lead and airborne lead exposure concentrations for battery workers were substantially higher in developing countries than in the United States. This disparity may worsen due to rapid growth in lead-acid battery manufacturing and recycling operations worldwide.
Several countries label lead acid as hazardous material, and rightly so. Lead can be a health hazard if not properly handled. Lead is a toxic metal that can enter the body by inhalation of lead dust or ingestion when touching the mouth with lead-contaminated hands.
Vented lead acid: This group of batteries is “open” and allows gas to escape without any positive pressure building up in the cells. This type can be topped up, thus they present tolerance to high temperatures and over-charging. The free electrolyte is also responsible for the facilitation of the battery’s cooling.
The batteries contain large amounts of lead either as solid metal or lead-oxide powder. An average battery can contain up to 10 kilograms of lead.