Gasman good point about the price of oil to synthetic, but lets be honest, it is not beyond the petroleum companies to throw oil increase into it somewhere, be it from increase in energey cost to produce it, higher demand and lower supplies.
You name it, any petroleum company regardless if the particular product is not crude oil based, will find away to get an increase in price and blame it on the oil prices. That and I am not sure but even in the process of the chemicals-oil is factor somewhere, much the same as it is in plastics and about everything else.
I mean after all Exon and the rest did seem to have the highest profits ever when the price of oil was up last year, it would seem that not only did the increase create a higher cost in fuel and other petroleum products, but they sure found away to add an even higher profit margin to those cost!!!