The record
Rohl, Langer et al.'s 1976 analysis of consumer talcums (PMID 1011287) found 10 of 20 products contained detectable tremolite and anthophyllite — 'principally asbestiform, while some also contained fragmented forms' — at levels 'from tenths of a percent to over 14% by weight,' with two products containing detectable chrysotile.
Claim scope
The 10-of-20 detection result with its concentration range and chrysotile finding, from the abstract of the published study.
What this source does not establish
Rohl and Langer themselves later wrote that 'we do not refer to anthophyllite and tremolite fibers in these talcums as asbestos' — this cleavage-fragment caveat originates with the study's own authors and must travel with the citation. The 14% figure is context for the later 0.5% J4-1 threshold debate, not a finding about any currently marketed product.
Limitations
Always pair the detection figures with the authors' own terminological caveat.
Source
Pmid — 1011287