How do I handle a long gap on my résumé? after 18 years as a machine operator

My résumé shows a gap from a layoff and some health issues. I am in Honolulu, in case local advice matters. I am not sure how much to explain. What do you say in interviews?

I was hired after a 10-month gap. The manager said the skills test mattered more than the dates.

I listed the volunteering and course under the same dates and kept the explanation to a sentence in the cover letter.