In its service announcement, the company said: "Avoid prolonged skin contact with the charging cable and connector when the charging cable is connected to a power source because it may cause discomfort or injury."

"Sleeping or sitting on the charging cable or connector should be avoided," the company warned.

Apple also warned people that charging or using iPhone in any area with a potentially explosive atmosphere, such as areas where the air contains high levels of flammable chemicals, vapors, or particles (such as grain, dust, or metal powders), may be hazardous.

"Exposing iPhone to environments having high concentrations of industrial chemicals, including near evaporating liquified gasses such as helium, may damage or impair iPhone functionality. Obey all signs and instructions," the company said.

The company further warned: "iPhone and Apple USB power adapters (sold separately) comply with required surface temperature limits defined by applicable country regulations and international and regional safety standards. However, even within these limits, sustained contact with warm surfaces for long periods of time may cause discomfort or injury."
The company asked people not to sleep on a device, power adapter, or wireless charger, or place them under a blanket, pillow when it’s connected to a power source

"Use common sense to avoid situations where your skin is in contact with a device, its power adapter, or a wireless charger when it’s operating or connected to a power source for long periods of time," read the warning.

The company said iPhone, the power adapter, and any wireless charger should be kept in a well-ventilated area when in use or charging.

Apple also highlighted the trouble of using third-party chargers and said: "You can also charge iPhone with “Made for iPhone” or other third-party cables and power adapters that are compliant with USB 2.0 or later and with applicable country regulations and international and regional safety standards."

"Other adapters may not meet applicable safety standards, and charging with such adapters could pose a risk of death or injury," the company said.

"It’s important to keep iPhone, the charging cable, the power adapter, and any wireless charger in a well-ventilated area when in use or charging. When using a wireless charger, remove metallic cases and avoid placing metallic foreign objects on the charger (for example, keys, coins, batteries, or jewelry), as they may become warm or interfere with charging," the company said.