Toxic

/ˈtɒk.sɪk/

adjective

Having a chemical nature that is harmful to health or lethal if consumed or otherwise entering into the body in sufficient quantities.
“Tobacco smoke contains many toxic substances.”
Appearing grossly unwell; characterised by serious, potentially life-threatening compromise in the respiratory, circulatory or other body systems.
“The child appeared toxic on arrival at the hospital.”
Severely negative or harmful.
“a toxic environment that promoted bullying”