The reason why they took Primatene Mist off the market is due to the use of Chlorofluorocarbon or CFC propellants which are harmful to the ozone layer.
Primatene Mist which was an over the counter asthma inhaler was taken off the market in 2011 due to the use of CFC propellants.
The CFC that is used as propellants in mists and sprays such as Primatene Mist are known to deplete the ozone layer which is a protective shield in the atmosphere of the earth.
In the year 1999 an international treaty banned CFCs worldwide to preserve the earths ozone layer.
And as part of implementing the treaty, the FDA also ordered makers of asthma inhalers with CFC propellants, including Primatene Mist to take them off the market in 2008.
In 2018, a new version of Primatene Mist containing HFA or hydrofluoroalkane propellants, which are permitted under current international and United States law was approved by the FDA and was reintroduced to the market.
There was no safety concerns about the Primatene MIST that caused it to be taken off the market.