MILWAUKEE, Wisconsin (WPVI) -- Doctors say they're seeing a new danger they believe is tied to vaping.Children's Hospital of Wisconsin says that in recent weeks, it has treated 8 teens with severe lung damage.All said they had been vaping in the weeks before they got sick.The hospital says some teens were in the ICU, and needed significant help just to breathe.One remains hospitalized.They had a wide range of ages; the first case was in June, the most recent was this week.Wisconsin state health officials are investigating whether the lung damage was caused by a bad batch of nicotine liquid, or other factors.Some parents weren't even aware their children vaped.Now, they are seeking answers to the life-threatening crisis and also urging other parents to be aware of what their children are doing.Doctors at Wisconsin Children's say vaping is a dangerous practice, no matter what.