[DSH]

Somehow I doubt the Supremacy Clause covers Executive Orders?

You are correct. Except that OSHA's yet-to-be-issued Temporary Emergency Standard would be in the nature of a federal regulation adopted pursuant to the federal Occupational Safety and Health Act. If the TES were found to be authorized by the OSH Act, it would have the force and effect of federal law and, under the Supremacy Clause, supersede anything the Texas governor (or Texas legislature) might do.

[Jan_Sobieski]

It would seem to me that a TES could easily be challenged, not being passed by Congress.

[indthkr]

"supersede anything the Texas governor (or Texas legislature) might do"

While the Texas governor's order may not stop entities from enforcing vaxx compliance, the Feds cannot stop Texas from levying fines and confiscating assets in violation of Texas law.