How widespread is phthalate contamination?

So widespread that the chemical signature of phthalates can be found in most samples being processed by chemical laboratories unless extraordinary care is taken to exclude them.

In fact, some laboratories have taken advantage of this ubiquity, without knowing it. It turns out that the signature of one set of phthalates is so ubiquitous, so predictably present in samples undergoing analysis, that its signature peak is used to calibrate mass spectrophotometers. It took CDC scientist John Brock's diligent detective work to discover the true source of that contamination.