All of the beaches in Avalon and Ocean City, 12 miles north, were closed for some portion of yesterday.

Stretches were reopened by mid-afternoon after cleanups and sweeps by police, firefighters, lifeguards, and public works crews to confirm that no additional medical waste had been found.

Two blocks in Sea Isle City were closed to swimmers after a syringe was found between First and Second Streets, and a small stretch was closed at the 2200 block of Commonwealth Avenue in neighboring Strathmere.

The week of on-again, off-again closures began in Avalon last Saturday, when between 100 and 200 syringes were found in the sand with gauze and other medical supplies. Some or all of the town's beaches have been closed a total of four times this week.

In Ocean City, beaches between 38th and 46th Streets were closed on Thursday after six syringes were found along with what appeared to be strips of shredded plastic and plastic foam mixed with seaweed.

By yesterday afternoon, Ocean City beaches from 34th Street north to the Longport Bridge had been reopened. Those from 35th Street south remained closed.

No one is sure what the plasticlike material is, said Kevin Thomas, director of the Cape May County Department of Health. Some officials believe it may be sunbaked seaweed.

In Avalon and Ocean City, authorities agreed to err on the side of caution. Health authorities said they were concerned that contact with the needles could result in tetanus.

"Public safety comes first and suntans come second," Avalon Mayor Martin Pagliughi said yesterday at an oceanfront news conference just before the Cape May County Health Department reopened the town's beaches from 32d Street south.

"I know a lot of people on vacation don't want to hear that, but we can't afford to have anyone injured in an incident like this," Pagliughi said.

Authorities in Avalon and Ocean City said a search early this morning will determine whether the beaches will be opened.

Peter Aseltine, a spokesman for the state Attorney General's Office, said the needles found in Ocean City, Sea Isle City and Strathmere appear not to be connected with some of those found in Avalon.

The syringes first found in Avalon were the treatment-type used by physicians. Those discovered there later, and also in the other beach towns, appear to be the in-home kind used by diabetics for insulin injections. Yesterday's tide brought Avalon more physician-type syringes.

The state is offering a $10,000 reward for information leading to the arrest and conviction of anyone involved in the Avalon incidents, Aseltine said.

Pagliughi said that the latest deposit - which included six syringes and medical waste officials declined to identify - may lead investigators to the source of the pollution, because readable serial numbers were on almost every item.

The mayor believes that the medical waste found last weekend was "placed," but that subsequent material washed in with the tide.

"There's no doubt in my mind that the first batch we found was deliberately set, and the batch we found today seems to be similar to what's washing up in Ocean City and in one to two other towns," Pagliughi said. "This material is waterlogged and looks like it has been in the water for quite a while."

Pagliughi said Avalon, which National Geographic Adventure magazine recently named one the "50 next great towns to live and play in," had been victimized. For many, the week has recalled ugly memories of the mid-1980s, when ocean pollution was common and trash, chemical drums, and medical waste often washed up at the Shore. Those incidents inspired federal laws prohibiting ocean dumping.

"It's a shame, it's a real shame, for the town, especially on a holiday weekend," Pagliughi said. "We're just glad it didn't happen on Memorial Day weekend, because that could taint the entire season."

Elizabeth Walsh, who owns a bakery and cafe called Isabel's on Avalon's main drag, Dune Drive, agreed.

"Something like this happening early in the season might make some people think twice about coming here," Walsh said.

"But I think by now, the people who live here or have summer homes here are so loyal to the town, they realize that what happened isn't the fault of anything the town has done," she said.

Her neighbor Kate Horner, who operates the Avalon Surf Shop, said she could not think about the effect of the incidents on her business.

"I'm more concerned about the safety of the people on the beach than whether or not they'll come down and shop in my store," Horner said. "I think that's the attitude of pretty much everyone here, and I think that's why people are so loyal to Avalon."

Michele Gillian, executive director of the Ocean City Regional Chamber of Commerce, said her member merchants remained optimistic about the Labor Day weekend.

"It's not the best of times, but I don't think it colors the image of the town, because I think people realize this is an isolated problem and not the kind of thing that was going with the ocean dumping in the 1980s," Gillian said.

"I haven't heard about any mass cancellations from the hotel and motel people," she said, "and I think that the public appreciates that we are all taking precautionary measures to protect them."