See Shu"t Shulchan Levi 24:15 (page 232).
Rav Belski zatza"l (formerly the posek for the OU) is discussing the kashrus status of equipment used to manufacture vegetable oil produced with no hechsher, or with a "non-acceptable" hechsher.
He writes that there are real concerns about non-kosher oil being mixed in, or at least having the ...
1- many use rav moshe on pasteurized wine
2- carrying grapes only by mashgiach is a stringency
3- one can still get non glatt from reliable kosher agencies
4- less checking and less openness is the main problem. If that was fixed then other problems would go away.
Also if rabbi lopatin,a rather understanding individual, could not consider it reliable... ...
Yes ,according to the Rashba there is a prohibition of gid hanashe by a human. This is brought in the Mishneh Lamelech al HaRambam 8:1 .
Text of Mishneh Lemelech:
גיד הנשה נוהג בבהמה וחיה הטהורים. נ"ב איסור גיד הנשה נוהג אף באדם כ"כ הרשב"א סי' שס"ד יע"ש:
For further discussion see the Darkei Teshuva hilchos Dam 65 where there is a ...