Mold or Efflourescence?

In a damp crawlspace this white/brown substance was forming on several exposed areas where the vapor barrier did not cover. Very powdery, which makes me think efflorescence, though it looks very similar to some pictures of white mold I have seen.

Thoughts?

Isaac McPhee
Strong Foundations Home Inspection
Renton, WA

If it is mold, it is soil mold. Way different than the few molds that are considered toxic in an indoor environment. No worries!