McDonald's has selected a new trans-fat-free oil for their french fries, but they're not saying where it is being used. The new oil is being used in 1,200 undisclosed restaurants of their 13,700 total restaurants.
For McDonald's it's always about mitigating potential liability (with healthy food offerings that no one eats and by promoting a 'healthy lifestyle' that everyone ignores...people don't eat at McDonald's for their health) and putting a healthy PR spin on their operations (by hiring 'professionals' like personal trainer Bob Greene and Dr. Dean Ornish to legitimize their 'healthy image'). Their refusal to reveal where the new trans-fat-free oil is already being used is part of this mindset. They get the positive PR of eliminating trans-fat from (some of) their fries without having to offer full disclosure and risk groups and/or individuals complaining that a given McDonald's doesn't offer the healthier fries.
Not to mention the fact that I'm sure McDonald's has thousands of gallons of the old trans-fat-rich oil that they want to be sure they use up before they move on to something that's better for your health...after all, their bottom line always comes first.