We investigate the lifetime of two-electron spin states in a few-electron Si/SiGe double dot. At the transition between the (1,1) and (0,2) charge occupations, Pauli spin blockade provides a readout mechanism for the spin state. We use the statistics of repeated single-shot measurements to extract the lifetimes of multiple states simultaneously. When the magnetic field is zero, we find that all three triplet states have equal lifetimes, as expected, and this time is similar to 10 ms. When the field is nonzero, the T-0 lifetime is unchanged, whereas the T_ lifetime increases monotonically with the field, reaching 3 sec at 1 T.