As I read the letters complaining about cane burning, I can't help but wonder how many writers are transplants from the Mainland.
Studies suggesting alternatives for harvesting are from other countries that don't have the unions to deal with demanding a higher wage and benefits adding to higher costs. Health care is standard in Hawaii, but other benefits like retirement are also costly. Nor do they have the high-cost federal and state taxes of doing business.
Without the cane fields the entire region would become a barren wasteland. If you believe cane burning is a hazard, wait until the dust blows through Kihei, Maalaea and Wailea when there are no cane fields. Next time you see a harvested cane field, notice the dust from the wind. Now imagine no cane fields and, of course, the dust on a much larger scale.
Be careful what you wish for, the alternative is much worst.