del·e·te·ri·ous 
/ˌdɛləˈtirijəs/ adjective
/ˌdɛləˈtirijəs/ adjective [more deleterious; most deleterious] formal : damaging or harmful
▪ The chemical is deleterious to the environment. ▪ The drug has no deleterious effects on patients.
▪ The chemical is deleterious to the environment. ▪ The drug has no deleterious effects on patients.
