What underground gas is referred to as "choke" or "blackdamp"?

The gas referred to as "choke" or "blackdamp" is carbon dioxide. This term is commonly used in mining and ventilation contexts to describe the condition when high levels of carbon dioxide accumulate in underground spaces, leading to potentially hazardous situations. Carbon dioxide is a colorless, odorless gas that can displace oxygen in the air, thus creating an environment that is dangerous for miners.

In high concentrations, carbon dioxide can cause symptoms such as headaches, dizziness, confusion, and even loss of consciousness, due to its displacing effect on breathable air. Therefore, understanding and monitoring the levels of carbon dioxide is crucial for ensuring the safety of underground operations. Proper ventilation systems are necessary to dilute and remove this gas from work areas.