Yes it is safe to use. During the development of our products, our products are tested to ensure that they withstand transport and storage in a variety of temperatures, including the temperatures common among warmer and colder climates within the U.S, without compromise to product performance. At home, be sure to store in a cool place, away from direct sunlight. Due to extremely cold weather in some parts of the country, the color kit you ordered may arrive with the contents frozen. The cold will not affect the quality or effectiveness of your color. It just needs to thaw at room temperature before you can use it.