I do find it intriguing that Now does does not state on their site that their product (which I believe is not made in the US) has any USP classification and they also use the non standard Glycerine spelling, which is also inconsistent with the USP's monograph.
NOW Foods - Vegetable Glycerine - 4 fl oz
"NOW® Vegetable Glycerine is a USP and food grade, all natural product derived from vegetable oil."
Looks like the labs and facilities are in Bloomingdale, Illionois although it doesen't state specifically that is where the glycerine is made.
NOW Foods - NOW Facility
"Experienced, educated, and highly trained technicians rely on the latest technology to
perform a variety of tests throughout the entire manufacturing process. These include Identity, Potency, Microbial, Organoleptic, and Contamination. And while each type of test is important in manufacturing quality products, Microbial testing is critical in ensuring that NOW products are safe and free of biological contamination. A technologically-advanced,
in-house microbiology lab that allows NOW scientists to provide unparalleled quality microbiological control in a timely manner, using rapid method analysis."