Server Administration :: Delete Statements UseTemp Tablespace?

Why large delete statements, with no where clauses, could be using up temp tablespace segments? I thought temp tablespace was just for sort operations,joins, etc.

We have a weekly job that inserts rows into a staging table, deletes, with commit, the a few minutes later and repeats the process. Each delete is using some of the temp tablespace. Eventually we run out of space (ora-01652). That's another thing. I would have thought the space would be released for the next process, but it's now.

SNAP_TIME USERNAME SESSION_ADDR SESSION_NUM MB SQLHASH SQLADDR SQL_TEXT
2011-06-15; 19:10 SCHEMA_USER 0700000209286B00 49680 980 3165065004070000020A8F9F20 DELETE FROM SCHEMA.FIN_RECORDS_TO_EVAL
2011-06-15; 19:15 SCHEMA_USER 070000020F2A7670 10601 275 3165065004070000020A8F9F20 DELETE FROM SCHEMA.FIN_RECORDS_TO_EVAL
2011-06-15; 19:20 SCHEMA_USER 070000020925FE38 19368 4748 3165065004070000020A8F9F20 DELETE FROM SCHEMA.FIN_RECORDS_TO_EVAL
2011-06-15; 19:25 SCHEMA_USER 070000020925FE38 19368 15783 3165065004070000020A8F9F20 DELETE FROM SCHEMA.FIN_RECORDS_TO_EVAL

We will probably switch to truncate statements, but this situation really puzzles me. I've tried view the docs but don't see any of delete statements using temp tablespace.