Waste is generally considered hazardous if it (or the material or substances it contains) are harmful to humans or the environment.
Examples of hazardous waste include:-
asbestos / chemicals, such as brake fluid or print toner / batteries / solvents / pesticides / oils (except edible ones), such as car oil / equipment containing ozone depleting substances, like fridges / hazardous waste containers.
(Source: www.gov.uk/dispose-hazardous-waste – 23.04.20 )