Generalized torsion in amalgams

We give a condition sufficient to ensure that an amalgam of groups is generalized torsion-free. As applications, we construct a closed 3-manifold whose fundamental group is generalized torsion-free and non bi-orderable; a one-relator group which is generalized torsion-free and non bi-orderable; and a group which is generalized torsion-free and non left-orderable.