ASTM is a set of materials
testing standards that everyone agrees on, such as hardness of steel, air pressure, weights and measures reporting etc. But there is no actual testing organization and no “listing”. In fact there are no real electrical standards associated with ASTM, other than some esoteric ones such as ways to measure emissions, things like that. The use of those terms in response to a question about UL product listing would be a red flag of obfuscation to me: meaning they don’t have it and are worried about that so they bring up something else in hopes that you don’t know what it means and will accept it in lieu of UL listing.
As to whether or not you need “listing”, that is usually something required by some States (28 at last count) but some states don’t require anything at all and the NEC itself is somewhat vague about it. Whether a State requires it is usually determined by State amendments to the NEC, aka “State Codes” in some cases, or by State worker safety tegulations. But if required in your State, it’s generally NOT going to insist on UL itself, but rather a listing by an NRTL; Nationally Recognized Testing Lab, of which UL is just the most widely known and who creates and maintains most of the testing standards themselves (meaning other labs test and list items, but do so using UL’s standards).
OSHA maintains a list of accepted NRTLs and most states that require it will reference that list, although some states have their own and may be shorter or longer (often favoring local labs).
OSHA itself however actually
DOES require NRTL listings for equipment used “in the workplace”, so if this facility has “workers”, it is going to need it. OSHA of course is not a policing agency, but they are Judge, Jury and Executioner for employers. So for example if the employer of these chargers has an accident that triggers an OSHA investigation, and the devices in question are in any way involved, OSHA could shut them down in a heartbeat. Do people often ignore that risk to their business? All the time. But that doesn’t make it OK to ignore it.
