By Scott Haggett

CALGARY, Alberta (Reuters) - Enbridge Inc
has not been forced to ration oil shipments on its North
American pipeline system because of its Michigan oil spill, a
company executive said Thursday.

Steve Wuori, president of Enbridge's liquids pipelines
division, said space on some of the Canadian company's other
lines is tight following the July 26 rupture, which spilled
more than 800,000 gallons of oil sands crude into a Michigan
river system near Kalamazoo.

However the company has not been forced to tell oil
producers to limit shipments on its other lines -- a practice
called apportionment -- despite the loss of 190,000 barrels per
day of capacity on the ruptured Line 6B.

"We have not needed to apportion yet," Wuori said on a
conference call. "Certainly, some of the lines are very much at
capacity and storage levels generally are high upstream (of the
spill) just because of the restricted flow into downstream
markets."

Line 6B is part of Enbridge's massive pipeline system that
carries the bulk of Canadian crude oil exports to the United
States. The segment, which originates in Griffith, Indiana,
carries oil to refineries in the U.S. upper Midwest and the
Sarnia area of southern Ontario, which produce more than
700,000 barrels of fuel a day.

Three of the refineries that depend on oil from the broken
line have had to cut production. United Refining Co, which
which runs a 65,000 barrel a day plant in Warren, Pennsylvania,
warned on Wednesday that fuel shortages are possible if the
outage goes on much longer.

NO TIME ON RESTART

The break near Marshall, Michigan, spilled about 19,500
barrels of Cold Lake blend crude into a tributary of the
Kalamazoo River. Cleanup operations are still under way.

Enbridge can still not say when it will be allowed to
restart the line. Earlier this week U.S. regulators rejected
plans to resume oil shipments because they want the pipeline
operator to investigate at least four other sections of line
where testing showed anomalies similar to one at the site of
the rupture, as well as conduct pressure tests.

The company has until Friday to file revised plans with the
U.S. Department of Transportation's Pipeline and Hazardous
Materials Safety Administration, a deadline Enbridge expects to
meet.

It also plans to excavate and test other sections of the
line in addition to those requested by the regulator.

"In addition to the four that were requested ... we will
probably propose a few additional dig locations," Wuori said.
"I won't attempt to define a timeline for all of that."

Enbridge shares fell 1 Canadian cent to C$50.44 on the
Toronto Stock Exchange while Enbridge Energy Partners,
its U.S. affiliate, fell 44 cents to $54.95 in New York.

($1=$1.04 Canadian)
(Editing by Rob Wilson)