Environmental is pretty huge. Includes CO2 emissions and [antibiotic-resistance superbugs](https://en.wikipedia.org/wiki/Antibiotic_use_in_livestock) (and [superbugs caused by C02 emissions](http://www.iflscience.com/health-and-medicine/melting-permafrost-could-thaw-a-smallpox-graveyard-in-siberia/) for that matter). You could call that ethics but it is broader than animal welfare. Health is mentioned a lot, although that seems to be a reason people who are not vegan think they might go vegan. I think my health has improved along with going vegan but my diet is not pristine at all and I did not magically become thin.