Burn through the pipe wall during thermic welding may cause...

Burn through the pipe wall during thermic welding can lead to product release because it compromises the integrity of the pipeline. When a burn through occurs, it creates an unintended hole or opening in the pipe, which can allow the contents within the pipe, such as gas or liquid, to escape. This not only creates a safety hazard but can also cause environmental concerns, especially if the released product is hazardous.

In the context of pipeline operations, maintaining the structural integrity of the pipe is critical to preventing leaks and ensuring safe transport of materials. While other factors like bond failure and potential corrosion are relevant considerations in welding and pipeline integrity, the immediate and most significant consequence of a burn through is the potential for product release, making it the correct answer in this context.