After the helmet is subjected to a huge external impact, which of the following treatment methods should be adopted?

When a helmet has endured a significant external impact, discarding it is the best practice. Helmets are designed to absorb impact energy, and even if no visible damage is apparent, the internal structure may have been compromised. This could seriously affect its protective capabilities in any subsequent impacts.

Continuing to use a helmet that has been subjected to a large impact poses a risk, as it may no longer meet safety standards. Similarly, inspecting for visible damage alone is insufficient, as many detrimental effects can occur internally and remain unseen. Repairing and reusing the helmet is also not advisable, as manufacturers typically recommend replacing a helmet after any significant impact to ensure safety.

Thus, the method of discarding the helmet after such an event is a proactive approach to maintaining safety standards and ensuring the wearer’s protection in the event of further accidents.