virtually safe dose

initialism: VSD
https://doi.org/10.1351/goldbook.16190
Human exposure over a lifetime to a carcinogen which has been estimated, using mathematical modeling, to result in a very low incidence of cancer, somewhere between zero and a specified incidence (e.g., 1 cancer in \(\pu{1000000}\) exposed people).
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1332 [Terms] [Paper]