Analysis of current spikes associated with pitting events was performed on high purity Al loop wire electrodes over a range of Cl- concentrations (10(-4) to 1M) and potentiostatically applied potentials. A distribution of pitting and repassivation potentials was observed at each Cl- concentration. Factors controlling the transition from metastable to stable pitting were identified by comparing the electrochemical behaviors of stable pits at elapsed times equal to the mean lifetime of metastable pits. This comparison also provided insight on the origins of statistical distributions of pitting potentials. The key differences were that (i) stable pits had a faster rate of rise in pit current which implies a faster growth rate and, subsequently, larger pit radii at times equal to metastable pit lifetimes, and (ii) stable pits satisfied the criterion I(pit)/r(pit) > 10(-2) A/cm, at all times during growth, indicating that a concentrated AlCl3 solution must be maintained for pit survival. However, the pit growth rates were ohmically limited near the pitting potential. Chromate inhibitor decreased the metastable pit nucleation rate and minimized pit growth rates so that the 10(-2) A/cm criterion was difficult to achieve; hence the chance for pit stabilization was reduced.