WASHINGTON (AP) _ E.I. du Pont de Nemours & Co. admits one of its plants improperly disposed of hazardous waste and says it will pay the government a $1.85 million penalty.

''Given the circumstances, we still think $1.85 million is a significant fine, and we don't feel there was any adverse effect on the health of our employees or the environment,'' said Richard Stewart, manager of Du Pont's Chambers Works facility in Deepwater, N.J.

''Nevertheless, they are violations and we have to stand up to that responsibility,'' Stewart said in an interview from the plant, which is New Jersey's largest hazardous waste treatment and disposal facility.

The settlement with Du Pont, based in Wilmington, Del., was one of 29 hazardous waste land disposal enforcement actions announced Friday by the Environmental Protection Agency and the Justice Department. Collectively, they would impose penalties totaling more than $5.35 million.

''Fouling of the nation's land and waters with hazardous waste will not be tolerated and violators should expect that the government will seek the full range of remedies, including significant penalties, permitted by law,'' Attorney General Dick Thornburgh said in a statement.

Although the various companies are connected only by their alleged violations, the enforcement actions were announced simultaneously ''so the regulated community gets the message that we're serious about particular laws and regulations,'' said EPA attorney Mimi Newton.

The $1.85 million penalty against Du Pont is the third largest such fine ever obtained under the Resource Conservation and Recovery Act, officials said. The largest, $2.78 million, was paid in 1989 by Environmental Waste Control in Indiana. The second largest, $2.5 million, was paid by the Browning-Ferris hazardous waste facility in Livingston, La., in 1988.

The Du Pont settlement will resolve disposal and testing violations of the ban on land disposal of hazardous wastes at the Chambers Works facility, the EPA said.

In addition to the fine, Du Pont must perform a compliance audit to ensure that the facility and other Du Pont facilities nationwide are meeting the land disposal restriction requirements. Du Pont also has agreed to perform certain pollution prevention activities, the EPA said.

A federal court must approve the settlement.

Another firm settling a hazardous waste disposal case is Paul-Munroe Hydraulics Inc. of Orange, Calif., which agreed to pay $60,000 through an administrative settlement that an EPA administrative law judge must approve, Newton said.

In addition to the Du Pont case, the Justice Department filed seven other judicial enforcement actions in U.S. District courts, seeking up to $25,000 per day per violation from each company. And the EPA took direct administrative enforcement actions against 20 facilities seeking a total of $3.4 million in penalties.

Asked why some companies face federal lawsuits rather than EPA actions, Newton said, ''In some cases it is because the gravity of the cases is larger. ... In most cases, we've tried to go after them in administrative ways, but it hasn't made any difference to the companies and they continue to violate the rules.''

Three of the seven companies facing federal lawsuits are accused of the actual land disposal of prohibited wastes. Newton identified those three as Chaparral Steel Co. of Midlothian, Texas; Columbia Mfg. Co. Inc. and MTD Products, Inc., of Westfield, Mass.; and Structural Metals Inc. of Seguin, Texas.

The four other companies facing a variety of charges such as storing waste longer than time limits set by regulations are Cablec Industrial Cable Co. of Marion, Ind.; Grumman St. Augustine Corp. of St. Augustine, Fla.; National Rolling Mills Inc. of Paoli, Pa., and Proteccion Tecnica Ecologica Inc. of Penuelas, Puerto Rico.

As for administratively imposed penalties, the companies facing the largest are the Boeing Co., Everett, Wash., $620,475; Universal Mfg. Co. Inc. of Algona, Iowa, $511,535; and Handy and Harman Automotive Group Inc. of Archbold, Ohio, $429,650.

Next in size of fines are Ciba-Geigy Corp. of McIntosh, Ala., $245,100; Stone Container Corp. of Panama City, Fla., $244,800; Nox-Crete Inc. of Omaha, Neb., $241,118; Asea Brown Boveri Inc. of Windsor, Conn., $197,230; and Western Lighting Standards Inc. of Perris, Calif., $150,000.

Also facing fines are New England Plating Co. Inc. of Worcester, Mass., $139,230; Universal-Rundel Corp. of Ottumwa, Iowa, $138,633; Allen-Morrison Inc. of Lynchburg, Va., $133,000; SAIC of San Diego, Calif., $119,500; and Southwire Corp. of Jewett City, Conn., $113,325.

Facing smaller fines are Rapid Circuits, Inc., of Levittown, Pa., $61,812; Rochester Corp. of Culpeper, Va., $40,000; B.F. Goodrich of Spencer, W.Va., $32,000 and Olson Wire Products Co. Inc. of Baltimore, $25,499.

The Charleston Naval Shipyard in Charleston, S.C., and the Umatilla Army Depot of Hermiston, Ore., face administrative actions but no penalties.