Petrolatum
In plain terms
The petroleum jelly in Vaseline and countless ointments, one of the most effective and inert barriers known, used on newborns and after surgery. The internet scare about it traces to a contaminant found in crude, unrefined material, which refining removes; the cosmetic and pharmacy grade is clean.
What the evidence shows
Petrolatum is the occlusive in petroleum jelly, an FDA-approved skin protectant that locks in moisture and shields healing skin, which is why it shows up in everything from lip balm to diaper cream to post-procedure aftercare. The recurring worry is that, being petroleum-derived, it carries carcinogenic polycyclic aromatic hydrocarbons. That risk belongs to crude or incompletely refined petrolatum, not to the refined material used in cosmetics and drugs. Refining strips the PAHs out, the FDA requires cosmetic and pharmaceutical petrolatum to be highly refined within set purity limits, and Health Canada reports finding no unacceptable PAH impurities in the petrolatum in its market's products. The honest wrinkle is transparency: the EU bans petrolatum unless a maker can document the full refining history, while the US does not require that paperwork, so in theory a poorly sourced product could differ. In practice, refined petrolatum is chemically inert, is not absorbed into the body, and is one of the gentlest occlusives there is. The petroleum origin alone is not the problem, the same base material runs through much of modern life; refinement is what matters, and the grade in real cosmetics clears it.
On the label
Listed as petrolatum, white petrolatum, or petroleum jelly. White petrolatum and USP or pharmaceutical grade signal the refined material; if you want certainty on sourcing, favor brands that state their petrolatum is fully refined, since US labels are not required to.