It seems this is another example of regional variations in word usage. From the comments of British players, it would appear that safflower oil has not been widely used in the UK. It certainly has been used widely here in Australia, and it wouldn't have occurred to me to doubt its common status.
(Although now I check, I see it is no longer a mainstream grocery product here, but is offered by specialist retailers as a health food. Probably RM is right in surmising it has been largely supplanted by canola oil. I hadn't noticed this shift, as I'm an olive oil man myself - plus some peanut oil for stir-fries and other Asian style dishes. But I digress.)
The regional variation is confirmed by noting that safflower appears 14 times in the British National Corpus, but 144 times in the Corpus of Contemporary American English. The latter corpus is just under 4 times the size of the British one, so the word seems to be around three times as common in the US as in the UK.
In the last 12 months, the New York Times used the word 10 times; the Times of London only once. Also, I notice that among the uses of the word by the English paper over the past several years, quite a few of them relate to dyes made from the safflower plant, rather than the edible oil.
So, probably the word shouldn't have been used as a nine-letter word.
