There are some dangerous goods that passengers and crew are permitted to carry.  Please see the What Can I Carry? for a list of dangerous goods which can be carried either on one’s person, in cabin or checked baggage.

Some dangerous goods are required to be aboard the aircraft such as:

items for airworthiness or operating reasons or for the health of passengers or crew,  such as batteries, fire extinguishers, first-aid kits, insecticides, air fresheners, life rafts, escape slides, life-saving appliances, portable oxygen supplies, tritium signs, smoke hoods, passenger service units; and

electronic devices such as electronic flight bags, personal entertainment devices, containing lithium metal or lithium ion cells or batteries and spare lithium batteries for such devices carried aboard an aircraft by the operator for use on the aircraft during the flight or series of flights, provided that the batteries meet the provisions applicable to the carriage of portable electronic devices containing lithium or lithium ion cells or batteries by passengers. Spare lithium batteries must be individually protected so as to prevent short circuits when not in use. Please refer to ‘Consumer Articles’ in What Can I Carry?