Ethephon is a plant growth regulator used to promote fruit ripening, abscission, flower induction, and other responses.
Ethephon is registered for use on a number of food, feed and nonfood crops, greenhouse nursery stock, and outdoor residential ornamental plants, but is used primarily on cotton.
However this is used in many fruits, as well as grains like wheat and rice we commonly find in supermarkets, and there is no way to know.
More worrying, it remains in the rind and deeper into the fruit, so will accumulate with processing (juices, wines)
It is known to be toxic, yet continues to be approved around the globe
Ethephon often used on wheat, coffee, tobacco, cotton, and rice in order to help the plant’s fruit reach ripeness more quickly
https://timesofindia.indiatimes.com/city/vijayawada/ethephon-replaces-carbide-as-fruit-ripening-agent/articleshow/82360064.cms
Food chemicals : Ethephon
The ban on calcium carbide to ripen fruits has brought another chemical to the market — ‘Ethephon’. Used extensively to ripen fruits, experts say that the chemical is equally dangerous to public health. Ethephon is registered as an insecticide. It is sold in sachets and is widely available in the market.