harmful substance

synonym: noxious substance
https://doi.org/10.1351/goldbook.15754
Substance that, following contact with an organism, can cause ill health or adverse effects either at the time of exposure or later in the life of the present and future generations.
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1232 [Terms] [Paper]