Which of the following can trigger an explosion in a chemical plant?

An explosion in a chemical plant can be triggered by equipment failure due to the critical role that machinery and systems play in the safe handling and processing of hazardous materials. Equipment such as reactors, pressure vessels, and piping systems must operate properly to maintain control over chemical reactions and prevent the release of flammable substances. When machinery malfunctions, it may lead to leaks, overheating, or other dangerous conditions that create an environment conducive to explosions.

In contrast, options that involve proper handling of materials and adherence to safety protocols are designed to mitigate risks and prevent incidents. These practices are integral to ensuring a safe working environment and do not trigger explosions. Moreover, the absence of training programs pertains to organizational weaknesses in safety culture, which may indirectly lead to unsafe conditions, but it is the immediate failure of the equipment itself that can directly cause an explosion. Thus, equipment failure is a direct trigger for such dangerous events in a chemical plant.