CREATE TABLE table_55864 ("CERCLIS ID" CLOB, "Name" CLOB, "County" CLOB, "Proposed" CLOB, "Listed" CLOB, "Construction completed" CLOB, "Partially deleted" CLOB, "Deleted" CLOB)

In what county is the entry that has a Construction Completed date of 07/19/2000 and a Listed date of 09/21/1984 located?
SELECT "County" FROM table_55864 WHERE "Listed" = '09/21/1984' AND "Construction completed" = '07/19/2000'
SELECT "County" FROM "table_55864" WHERE "Construction completed" = '07/19/2000' AND "Listed" = '09/21/1984'