We refer to Mr Bachan Singh's letter (More questions on used electric car batteries, April 3).

Hybrid and electric car batteries contain mostly iron, copper and aluminium, and can be properly treated and recycled with the right technology.

They also contain lithium and cobalt, which can be extracted using commercially available technologies adopted by electronic waste recyclers.

All e-waste recyclers must have the necessary pollution control equipment to meet the National Environment Agency's emissions and discharge standards.

Lithium-ion batteries are not hazardous, while nickel metal hydride batteries are hermetically sealed to prevent materials within them from escaping into the environment.

In the case of nickel metal hydride batteries, after they are dismantled, any nickel waste must be collected and disposed of by a licensed toxic industrial waste collector under the Environmental Public Health (Toxic Industrial Waste) Regulations.

For further inquiries, members of the public are encouraged to write in directly to us at www.nea.gov.sg/corporate-functions/feedback

Desmond Tan

Director

Waste and Resource Management Department

National Environment Agency