2006 New York Code - Certificate Of Expenses.

 
    §  24-606 Certificate of expenses. Upon the completion of any response
  measure giving rise  to  a  lien,  the  city  agency  implementing  such
  response  measure  shall  file with the agency or agencies designated by
  the mayor pursuant to section 24-605 a  certificate  setting  forth  the
  work  done  and  the expenses incurred and certifying that such expenses
  were necessary and proper in the exercise  of  its  lawful  powers  and,
  where  applicable,  apportioning  such  expenses among lots or buildings
  belonging to  different  persons.  The  city  agency  implementing  such
  response  measure  shall  also  file  a copy of any notices of potential
  liability for such expenses it has mailed for purposes of paragraph  two
  of  subdivision c of section 24-605 and a statement reciting the date of
  any such mailing.