New data on the Be and B abundances in halo stars indicate a linear correlation with metallicity. Such a 'primary' behaviour of these light elements doesn't support the scenario where their production occurs in the interstellar medium, through spallation reactions. Be and B are probably produced in the oxygen-rich ejecta of type II supernovae. The right amount of those elements can be obtained if each supernova event converts about 10 51 erg into high energy particles and the irradiation time is about 100-1000 years. The positive detection of 6Li in HD 84937 constrains the early cosmic ray intensity to values comparable to those presently found in the galactic disk.