[OL]Help clarifying occupation title

Hello fellow listers,

On his marriage certificate, my grandfather's occupation was listed as "Neinbaucharbeiter" (we think. we're feeling good about the "Nein" and the "arbeiter"). We have no idea what this could mean, and it makes no sense. Any ideas? Anyone ever find an occupation similar to this?

Thanks in advance.
Kristin Schmidt Van Scoy