[en] Electron paramagnetic resonance (EPR) has been used to monitor oxygen vacancies and zinc vacancies in a ZnO crystal irradiated near room temperature with 1.5 MeV electrons. Out-of-phase detection at 30 K greatly enhances the EPR signals from these vacancies. Following the electron irradiation, but before illumination, Fe³⁺ ions and nonaxial singly ionized zinc vacancies are observed. Illumination with 325 nm laser light at low temperature eliminates the Fe³⁺ signal while producing spectra from singly ionized oxygen vacancies, neutral zinc vacancies, and axial singly ionized zinc vacancies. This light also produces EPR spectra from zinc vacancies having a OH^- ion at an adjacent oxygen site. The low-temperature response of the irradiated crystal to illumination wavelengths between 350 and 750 nm is described. Wavelengths shorter than 600 nm convert Fe³⁺ ions to Fe²⁺ ions and convert neutral oxygen vacancies to singly ionized oxygen vacancies. Neutral zinc vacancies are formed by wavelengths shorter than 500 nm as electrons are removed from isolated singly ionized zinc vacancies. Warming above 120 K in the dark reverses the effect of the illuminations. These wavelength-dependence results suggest that the ground state of the neutral oxygen vacancy is deep, approximately 1.3 eV above the valence band, and that the ground state of the singly ionized zinc vacancy is also deep, about 0.9 eV above the valence band