If it's excess methane, you won't sense it. This is why municipal gas has a smell agent added. The same cannot be done for space fuel. If it's hydrazine, it is

If it's excess methane, you won't sense it. This is why municipal gas has a smell agent added. The same cannot be done for space fuel. If it's hydrazine, it is about as smelly as gasoline but ammonia, I think, but the toxic dose is below the smell threshold. So no, you do not get to generalize here.