 Mayor Nagin and  the Orleans Parish School Board had been negotiating, aparently unsuccessfully, at least since June to use OPSB buses and drivers in an emergency.
<meaning-changed>  Mayor Nagin and  the Orleans Parish School Board had been negotiating, aparently unsuccessfully, at least since June to use OPSB buses and drivers in an emergency.
 Mayor Nagin and It is unclear whether Mayor Nagin knew these particular buses existed, since the Orleans Parish School Board had been negotiating, aparently unsuccessfully, at least since June to use OPSB buses and drivers in an emergency.