Why is low oxygen content necessary before opening a fire seal?

Low oxygen content is necessary before opening a fire seal primarily to reduce the likelihood of an explosive mixture. In confined spaces, such as underground mines, an appropriate balance of gases is crucial for safety. When oxygen levels are too high, it increases the risk of combustion and can lead to explosive conditions if there are flammable materials or gases present. By ensuring that the oxygen content is low, the chance of igniting an explosive mixture is minimized, which is vital in maintaining a safe working environment for miners.

The other answer choices do highlight factors that contribute to overall worker safety and comfort, but they do not specifically address the critical need to prevent explosions, which is paramount in mining operations where safety measures are integral to the protocols surrounding fire seals.