All money in an HSA is pre-tax, you have not paid any taxes on this money yet (unless you made the contribution yourself rather than through your employer and you failed to take a deduction for the contribution, but doing so only means that you overlooked the deduction, it does not create after-tax basis in your HSA).
All distributions from an HSA that are not used to pay for qualified medical expenses incurred after the HSA was established are subject to ordinary income tax and, if you are under age 65 at the time of the distribution, a 20% early-distribution penalty.
