An oil slick from the sunken tanker Haven is menacing the French Riviera for the first time, and workers struggled Wednesday to keep it from seriously fouling the region's famed beaches.

Tar and foamy mousse from the slick dotted small areas of Cap d'Ail, Beaulieu, Saint-Jean-Cap-Ferrat and Villefranche east of Nice during the night, regional authorities reported.The breadth of contamination was not regarded as serious. The slick, which is about 3 miles long, gathered about a half mile offshore late Tuesday, local authorities reported.

Four boats equipped to drain oil off the surface attacked the slick on Tuesday and resumed work at dawn. By midday, they had vacuumed up 11/2 tons of mostly solidified oil, tar, congealed mousse and other solids.

"These are practically solid residues, which is making our work easier," said a clean-up coordinator. "It's neither sticky nor oily."

Regional authorities Wednesday ordered local mayors to send emergency personnel to assist in cleaning up small spots of contamination on the area's pebbly beaches.

It marked the first time oil from the Cypriot tanker has reached French shores since the tanker sank April 14 off Arenzano, near Genoa in northern Italy, after spilling an estimated 6 million gallons.