"It's legal, but it's morally equivalent to reading people's mail," said James D'Entremont, a resident of Central Square.

John Roberts of the Civil Liberties Union of Massachusetts said that people should be able to expect that the city dispose of their trash without looking through it.

"It's one thing to look for felons, but it's another to be looking for Clorox bottles," he said.

Professor of Law Richard H. Fallon Jr. saidthat practice was legal according to recent courtdecisions. "But that doesn't mean it's a goodidea," he said.

D'Entermont criticized the search, whichrewarded people who complied with the ordinancewith prizes, for being "very culturally biased."

The prizes this month were $25 giftcertificates to Wordsworth Books. Last spring, thecity ran a similar contest, with a $25 gift basketfrom Origins.

"I live in a neighborhood with many people onwelfare, immigrants leading stressful enough livewithout having to worry about recycling. It'sludicrous. People having the most problems with ittend to have the least use for the prizes,"D'Entremont said. "The prizes are for people who'behaved' themselves after surveillance. It'sludicrous.