Ultrasonic welding is also applied in the packaging of dangerous materials, such as explosives, fireworks and other reactive chemicals. These items tend to require hermetic sealing, but cannot be subjected to high temperatures. One example is a butane lighter. This container weld must be able to withstand high pressure and stress and must be airtight to contain the butane. Another example is the packaging of ammunition and propellants. These packages must be able to withstand high pressure and stress to protect the consumer from the contents. When sealing hazardous materials, safety is a primary concern.