Measurements of impurity ion concentrations and energy distributions in the 2XII mirror device are desaibed. The measurements were made using a fast-pulsed gas valve and a charge-exchange analyser that employs both electrostatic and magnetic separation to obtain energy spectra of separate particle species. The predominant high-Z material detected wascarbon, having a concentration of ∼2% and a mean energy of 3-6 keV. Smaller amounts of oxygen were the only materialother than hydrogen detected. These energetic impurity levels are determined to be contained against self-scattering into themirror loss cones and to have only minor influences on plasma life-time and on mean ion and electron energy.