it was open till the late 1990's
you probably wont find any information on it as it was a ministry of defense site (i think)
there was (still is??) a paint (dulux) plant on the way into dumfries also
but its newer than ww2
dont know if you know this, but it was owned by nobels explosives
(the company that alfred nobel [the peace prize guy] set up to make dynamite http://en.wikipedia.org/wiki/Dynamite ) the first site was at ardeer, the second was powfoot
they made (and still do at ardeer as far as im aware) nitrocellulose and nitroglycerine
for propellants and other chemicals, intended for other nasty stuff

http://nobelprize.org/alfred_nobel/indu ... index.html
that has some cool info
also http://www.nobel-enterprises.com/ is the current company that owns the site