The Preschool said it wouldn't allow the EpiPen because after it has been used it exposed the needle, which could cause a safety concern for other children and the staff.
Other leading EpiPens available have a cover over the needle after use however they are more expensive and the family cannot afford it as the current one they are using is cheaper - which has been banned by the Preschool.
Even though there is Government Initiative that provides funding, the family doesn't qualify.
The city Of Westminister council has stood by their decision of banning the EpiPen due to safety reasons, however, are reviewing their policy and practices.
There is now a national Epi Pen shortage across the US, meaning it could take the family a month or more to receive one.
Reference:
"Policy Forced Parents To Pull Three Year Old Out Of Preschool", Yahoo7 News, 7 September 2018