The Supreme Court agreed yesterday to hear an appeal of a lower court ban on state laws intended to expand federal protections against oil spills.

The state of Washington, which filed the appeal, is supported by 10 other coastal and Great Lakes states.

The issue turns on the Waterways Safety Act of 1972, a federal law that authorizes the Coast Guard to establish vessel traffic systems and toughen minimum standards for tanker design, construction and operation.

Last August, a federal three-judge panel ruled that the act preempts a 1975 Washington law aimed at preventing pollution of Puget Sound, a Pacific inlet on which three of every five Washington residents live.

The decision was a victory for Atlantic Richfield Co., which operates a refinery at Cherry Point, Wash., adjoining northern Puget Sound, and for Scatrain Lines, Inc., which builds and operates tankers.

The Justice Department, invited by the Supreme Court to file a brief, contended in the lower court that the waterways act bars additional state laws under a provision of the Constitution making federal statutes "the supreme law of the land." The department said:

"In the final analysis, the question is not whether the design and operation of oil tankers should be regulated and controlled in the interests of marine environment, for it is common ground that such regulation is required.

"The question in this case is whether that control is to be exercised and the scope of the regulations determined by the federal government in the manner which Congress has prescribed, or whether those determinations are to be made by the inconsistent and diverse actions of the several states."

In a friend-of-the-court brief, however, Maryland, Delaware, Maine, Minnesota and New York said that they "cannot be expected to refrain from action while their marine resources are being destroyed or threatened by massive oil pollution from tankers . . ."

Five other states said that the decision "threatens state regulation of matters legitimately within its police power" as well as "existing and contemplated state laws on oil tanker operations in coastal areas not in conflict with federal law."

The Washington state law bars supertankers of more than 125,000 deadweight tons from Puget Sound. It also requires tankers of between 40,000 and 125,000 tons to have a tugboat escort or such safety features as twin screws and double bottoms under oil spaces.

ARCO, which filed a challenge to the law the day it was enacted, built the refinery to handle Alaskan crude oil, which is expected to arrive mainly in tanks of at least 12,000 tons. The company has been complying with the state law pending disposition of the litigation.

Saying that "inconsistent and diverse" state actions are "proliferating," ARCO emphasized "the need for national uniformity in the regulations imposed upon vessels engaged in interstate and foreign commerce."

In other actions by the court: PICKETING

In Chula Vista, Calif., Sears Roebuck and Co. had nonunion labor do some carpentry work. Union carpenters then peacefully picketed on walkways that surround the store.

The company got a state court injunction to bar the picketing on the ground that it was trespassing on the store's property.

But the california Supreme Court reversed 7 to 0, saying that the National Labor Relations Act gives the federal government exclusive jurisdiction over such disputes. Other state courts have ruled differently. Yesterday, the high court agreed to review the California decision. LAWYER MISCONDUCT

In 1970, an American Bar Association committee reported that mechanisms to discipline lawyers for professional misconduct were inadequate. The Ohio Supreme Court responded by imposing a $50 biennial fee on every attorney in the state to pay for a full-time disciplinary unit. The Cuyahoga County Bar Association sued, claiming that the fee was a tax and a denial of due process. Yesterday, the court affirmed a federal judge's decision upholding the Ohio Supreme Court.