From your link:
Prior to boiling water exposure, the rate of release from individual bottles ranged from 0.2 to 0.8 nanograms per hour. After exposure, rates increased to 8 to 32 nanograms per hour.

Belcher stresses that it is still unclear what level of BPA is harmful to humans. He urges consumers to think about how cumulative environmental exposures might harm their health.

To put things in perspective 1 nanogram = 0.0000000000022 pounds or 0.000000000001 kg for our non-American readers. That's eleven zeros to the right of the decimal point.

Let's say I fill my 1 liter Nalgene bottle with boiling water to keep my feet warm overnight. If the water in my bottle remained boiling all night long (say eight hours) and then I slammed the whole liter of water, worst case is I would imbibe 256 nanograms of BPA which is 0.00000000056 pounds of BPA.

Now if we look at O'Connor's & Chapin's often-quoted paper on the xenoestrogen effects of BPA we see he had to give dose of 1.5mg of BPA per kilogram of body weight per day for the entire gestation period to get any measurable effects.

Hmm, 256 nanograms equals 0.000256mg, so someone would need to drink 5859.4 liters of BPA-contaiminated water per kilogram of their weight daily for nine months to suffer these effects.

-Blast, Ph.D.