A charger’s internal parts continue to draw current and warm up a little while it is plugged in for hours on end. Particularly vulnerable to overheating are chargers that are inexpensive or fake. The plastic casing and insulation materials may deteriorate due to this gradual heating, generating tiny harmful gases like formaldehyde or volatile organic compounds (VOCs).

Even at low concentrations, frequent inhalation of these compounds can irritate the airways and cause persistent sneezing, coughing, or sore throats. The exposure may exacerbate symptoms for those who already have sinus issues or asthma. Constant exposure to these pollutants over months or years can cause allergic rhinitis, bronchitis, and in extreme situations, permanent lung damage.