Boron will do everything Borax does as long as some is in Aspartate form. Else you need Boric Acid aka Borax to reach certain areas.
Borax itself is NOT toxic or no more than salt but you will need to take my word on that. The issue is that it is mined and unless purified to USP or Pharma grade can have any amount of pollutants.
This is the same with Epsom Salt, you don't want to intake mined Epsom Salt only USP or Pharma grade.
A PDF to refute Big Brothers claim to not replace Bromides with Boric Acid...although I just saw some new insulation made from 100% Cotton dowsed in Boric Acid in the market place to replace Big Chem/Pharma products.