▁were ▁the ▁only ▁part ▁of ▁Aber de en ▁Pro ving ▁Gr ounds ▁within ▁Baltimore ▁County . ▁The ▁chemical s ▁at ▁these ▁sites ▁were ▁dump ed ▁in ▁open ▁p its , ▁with ▁no ▁pre ca utions ▁taken ▁against ▁ground water ▁cont am ination ▁and ▁few ▁records ▁kept ▁of ▁exactly ▁what ▁was ▁dump ed ▁where . ▁In ▁the ▁ 1 9 8 0 s , ▁ground water ▁testing ▁revealed ▁cont am ination , ▁and ▁on ▁February ▁ 2 1 , ▁ 1 9 9 0 , ▁the ▁area ▁was ▁listed ▁as ▁one ▁of ▁Super fund ' s ▁" most ▁serious ▁un control led ▁or ▁abandoned ▁ha z ard ous ▁waste ▁sites ." ▁Some ▁clean up ▁was ▁completed ▁in ▁the ▁ 1 9 9 0 s ▁but ▁most ▁remains ▁un fin ished . ▁These ▁sites ▁remain ▁off - limits ▁to ▁the ▁public ▁and ▁und e velop ed ▁due ▁to ▁extreme ▁cont am ination . ▁ ▁In ▁the ▁ 1 9 7 0 s , ▁W G U - 2 0 , ▁a ▁long wave ▁radio ▁station , ▁was ▁established ▁by ▁the ▁Def ense ▁Civil ▁P rep ared ness ▁Agency ▁( now ▁the ▁Federal ▁Emer gency ▁Management ▁Agency ▁( FE MA )) ▁near ▁the ▁Gra ces ▁Qu arters ▁chemical ▁weapons ▁site . ▁The ▁purpose ▁of ▁the ▁station ▁was ▁to ▁alert ▁the ▁entire ▁Eastern ▁se ab o ard ▁in ▁the ▁event ▁of ▁an ▁enemy ▁attack . ▁ ▁In ▁the ▁ 1 9 8 0 s , ▁Ch ase ▁became ▁a ▁part ▁of ▁the ▁zip ▁code ▁ 2 1