Which conditions are considered principal causes of an explosion or chemical release?

High temperature and hydraulic shock are indeed principal causes of explosions or chemical releases due to their significant impact on chemical reactions and material integrity. High temperatures can accelerate reactions, increasing the likelihood of rapid reactions that may lead to explosions. In addition, high temperatures can weaken materials, making them more susceptible to failure under stress, which could result in a breach or release of chemicals.

Hydraulic shock, also known as water hammer, occurs when there is a sudden change in fluid flow, which can create intense pressure waves. These waves can lead to mechanical failure of equipment, particularly in piping systems. If a vessel or pipe ruptures due to hydraulic shock, it can release hazardous chemicals into the environment.

In contrast, the other options present conditions that do not directly correlate with common causes of explosions or chemical releases. High humidity and cold temperatures, for instance, typically do not enhance the likelihood of such incidents. Similarly, low pressure and chemical stability, as well as low temperature and physical inertia, generally imply conditions that are less likely to facilitate explosive reactions.