We report on first demonstrations of CdSiP2-based optical parametric oscillators that are pumped by eye-safe Q-switched nanosecond laser sources operating at 1.57 μm. One device reached 40% optical conversion efficiency generating 10 mJ of energy near degeneracy in the 3 μm region. Angle tuning of a similar device through the middle infrared was demonstrated with the signal and idler waves being tuned from 2.28 μm to 5.05 μm.