Canadian and American aircraft crisscrossing 34,000 square miles of the North Atlantic today found no trace of an overdue Panamanian tanker carrying 8.2 million gallons of industrial fuel oil.

A search vessel plowed through patches of oil 10 to 50 feet in diameter, but a Coast Guard spokesman said it was impossible to know if the oil came from the missing 642-foot Grand Zenith or from the Liberian tanker Argo Merchant, which broke up on Nantucket shoals Dec. 21.

The Argo Merchant dumped its 7.6 million gallons of industrial oil into the Atlantic near the Georges Bank fishing grounds in the worst oil spill in U.S. Atlantic Coast history.

The missing 23-year-old Panamanian tanker with a chinese crew of 38 has been out of radio contact for five days. It was due Monday in Providence, R.I. The captain radioed Thursday that the ship had encountered bad weather between Nova Scotia and New England en route from England.

"It's not normal that you can't contact a ship," Coast Guard spokesman Richard Griggs said. "We've been trying nonstop" since Monday.

Griggs said the oil encountered by the search vessel was 45 to 60 miles from the Argo Merchant oil spill. A chemical analysis was planned to determined the oil's origin.

Water temperatures in the search area hovered near 40 degrees, Griggs said, cold enough to kill an immersed man in less than an hour.

Planes planned to end the search by nightfall and move the search area to the south on Wednesday. Additional planes may be called out, Griggs said.

Washington, it was announced that the Senate Commerce Committee will hold hearings Jan. 11 and 12 to probe recent oil spills in and near American waters.

Included in the inquiry will be the December groundings of the Argo Merchant and another Liberian tanker, the Olympic Games, in the Delaware River.

Chairman Warren G. Magnuson (D-Wash.) said the hearings will lay the groundwork for "new, tough tanker legislation."

In 1976, he said, 15 tankers with a total of a million deadweight tons were lost, making it the worst year in history for such accidents. The incidents, he said, "demonstrate the weakness of the Coast Guard's safety requirements."

In New York Wednesday, George Papadopoulos, the captain of the Argo Merchant, will return to the stand in U.S. District Court to testify at a liability hearing on the grounding of his vessel.