I get asked this a lot lately, the answer is it depends. Yes, you can take cover from Frags, but No, not from concussion or smoke grenades.
page 19 FRAG GRENADES .snip* "...since it is not the explosion itself which causes the bulk of the damage but the shrapnel flying around, if a Character had chosen to TAKE COVER when attacked by a frag grenade, only a result of 5 or 6 counts as a hit."
Not exactly, in a foxhole (donut cover), or INSIDE a vehicle, a bunker or a log and dirt, or sandbag fortification of any sort a character is completely safe against a grenade, even if it's thrown next to, well in range, but OUTSIDE of it. If it is thrown INSIDE it, a character is completely safe, even if it is in range, so long as it is standing OUTSIDE. In other words, if it is thrown inside, anyone inside would be hit, but everyone outside would be safe. If it is thrown outside, anyone outside and in range would be hit, but everyone inside would be safe, even if it is in range. If it is thrown on the top of a roofed cover it counts as being outside. On top of any open top cover (including open top vehicles) it counts as being inside.