Which of the following is not an unsafe precondition, according to hfacs

1.substandard practices
2.substandard conditions
3.substandard behavior
4.environmental factors

Is this homework?

We don't do homework, but I suspect you may find your answer here.

By the way, HFACS is an acronym for "Human Factors Analysis and Classification System". Each letter in an acronym should be capitalized.