Dupont went "Politically Correct" about 20 years ago. Part of that process was divesting themselves of Remington Arms and Dupont Gunpowder.
Don't quote me, but I believe that the official policy, companywide, is no weapons on any site, for employees, regardless of posting. Many sites are posted with the prohibition. The sign reads "No Weapons", to include whatever they perceive as a weapon. It isn't for "safety", but for legal liability. The same sort of folks who have a strong influence on the Delaware legislature also have a similar effect on corporate leadership. If you research it on the net, you will find that a preponderance of the Fortune 500s have similar policies. The only weapons that are politically correct are to be found on a LEO's hip.
Some states are trying to enact legislation to prevent employers from barring otherwise legally possessed long guns & pistols from cars in their parking lots.
Delaware is not one of them.