singular debris?

[Barbara Need]

When did debris become singular? Or has it been singular and is
its use as a plural newer? In the reporting I have seen (Chicago
Tribune) I have noticed several uses of a subject debris with a
singular verb--and that jars. There were also, in the same article,
and, if my memory serves, in the same paragraph, uses of debris
with a plural verb.

Barbara Need
University of Chicago--Linguistics