On the danger of pesticides in cottonseed oil, I would like to quote from
"The Goldbecks' Guide to Good Food" by Nikki and David Goldbeck (1987), pp.
293-4:
        "The knowledge that most agricultural products are routinely
sprayed with chemicals in the field causes some concern about the pesticide
residues in any of the oils extracted from them.  Monitoring has revealed
pesticides in samples of both crude and processed oils.
        For a while, cottonseed oil was especially criticized since cotton
is not traditionally raised as a food crop.  We have been informed,
however, that cotton raised for oil is grown mostly in Iowa, Nebraska, and
the Dakotas, not in the South.  The shorter growing season there prevents
maturation of the fiber-producing cotton boll which is the prime target of
persistant pests.  Thus, dependence on insecticides in growing cotton in
those areas is no greater than for other oil-bearing crops."

Perhaps others will have more recent information on this, or on oils
produced for consumption outside the U.S.

Anne Altshuler, RN, MS, IBCLC and LLL Leader in Madison, WI