There is a law about labelling insecticides so the information must be there somewhere. However, if it's available for home use you can feel fairly safe. Pyrethrum should be quite safe but may not work very well on whitefly as they quickly build up a resistance to most pesticides. If you are sure they are aphids, try using a spray with pirimicarb in it as this is specific to aphids, i.e. does not kill bees, ladybirds etc.
Pyrethrum kills all non-resistant insects.