By and large, rafting is reasonably safe with a much better accident rate than, say, mountain biking or skiing (or, for that matter, trekking). However, there are few government controls on Nepal’s low-end operators and in the early 2000s and in 2009 there were a couple of fatalities – the first in two decades, mind you.
Make sure the company supplies life jackets (and not ancient ones), helmets and a full first-aid kit, and satisfy yourself that the rafts are in good running order and that there will be a safety demonstration. There must be a minimum of two rafts, in case one capsizes. In high-water conditions or on any river more difficult than class 2, the rafts should be self-bailing and there should be safety kayakers to rescue “swimmers”. Most important of all, guides must be trained, certified (including first-aid certified), have experience guiding on the stretch of river in question, and speak adequate English – there should be an opportunity to meet guides before departure.
The more distant but potentially catastrophic safety concern is from landslides or rare GLOF or glacial lake outburst flooding events. If you hear an unusual, thunderous sound coming from upstream while you’re on or beside the river, scramble for high ground. A big wave might be coming.
Rafters have the same responsibilities to the environment as trekkers, particularly regarding firewood, sanitation and litter (see Conservation tips).