Table 1. BPA and BPS concentrations in 50 thermal paper receipt samples.

Chemical in paper	mg/g receipt	mg/8×12 cm receipt
BPA-positive (44%)	19.6±1.0	9.0±0.4
	(11.5–26.3)	(6.1–11.3)
BPS-positive (52%)	23.5±0.7	10.8±0.3
	(15.2–30.1)	(7.1–13.2)

Two (4%) of 50 papers tested did not contain either BPA or BPS and did not show any estrogenic activity in a MCF-7 breast cancer cell proliferation assay (data not shown). Values are mean±SEM, with the range of measured values given in parentheses. See Section S2 in File S1 for individual receipt data.