LEDs can be hazardous if they are damaged. Generally, LED lights should not cause a fire because of the nature of electricity flowing through circuits, which will actually just shut off before causing damage or potential harm to its surroundings.
LED lights are, fundamentally, semiconductors. These same semiconductors are used in every computer chip ever produced by the modern electronics industry. They were designed to be reliable and safe for use in computers, phones, tablets, etc.; however, they are not specifically designed for use as lightbulbs. The standard “Current” that these devices use is either DC or Pulse Width Modulated DC power. This means that if their electrical circuit malfunctions or has an issue that causes too much current to flow through them (much like how a short circuit occurs) they can heat up quickly since current passing through any conductor creates heat which radiates outward until it dissipates via convection (heat rises so it dissipates at the top).