RC car batteries, like any other type of battery, can be dangerous if not handled properly. Here are a few of the potential hazards associated with RC car batteries and how to safely use and handle them:

1. Overcharging: Overcharging a battery can cause damage to the battery and even cause a fire hazard. Always use a charger specifically designed for your type of battery and never overcharge the battery.

2. Overheating: Overheating a battery can cause damage to the battery and even cause a fire hazard. Always store your batteries in a cool, dry place and avoid leaving them in direct sunlight or in a hot car.

3. Overloading: Using a battery with a voltage that is too high for your RC car can cause damage to the motor and electronic speed controller, leading to a loss of performance and even causing a fire hazard. Always use the appropriate voltage and type of battery for your RC car, as specified by the manufacturer.

4. Short Circuit: Short circuit can happen when the positive and negative terminals of the battery come in contact with each other, it can cause the battery to overheat, release gas and even cause a fire. Always keep the battery terminals clean and make sure they are not damaged or bent.

5. Battery leakage: Battery leakage can happen when the battery is overcharged or over-discharged, it can also happen when the battery is stored in a high temperature environment. Always check the battery before using it, if there is any leakage, do not use it, and properly dispose of it.

6. Battery disposal: Batteries should not be thrown in the trash, they should be properly disposed of at a recycling facility. Improper disposal can lead to environmental hazards and potential fire hazards.

By understanding the potential hazards associated with RC car batteries and following proper safety guidelines, you can safely use and handle your batteries. Always follow the manufacturer's instructions for safe usage and if in doubt, consult with a professional.