MASON CITY — There is no filtering of Internet information at the Mason City Public Library — but there is a zero tolerance policy for misuse, a library official said today.

Some advocacy groups are pushing for Internet filters at libraries after an incident involving a homeless sex offender in Des Moines.

Police say James Effler Jr.  molested a toddler in a restroom at Des Moines' main public library. Effler told police he used library computers to view pornography many times, authorities said, but he had not logged on the day he was arrested.

Penny Moorehead, assistant director at the Mason City Public Library, said the American Library Association opposes Internet filtering and so does the Mason City library.

“The library association says it is like removing pages from a book. The Internet is one large book,” she said.

“Filtering information can  prevent people from having information they need,” said Moorehead. “If you filter out the word `breast,’ you also filter out all information on breast cancer,” she said.

Moorehead said the Internet area of the library is in a public location and is closely monitored. “We have a zero tolerance for anyone misusing it,” she said.

Dan Kleinman of Chatham, N.J., founder of the Plan 2 Succeed citizens group, wants all libraries to have Internet filters.

“This is a sad thing. Children are being raped and molested in public libraries, and it's often a result of pornography being available  in public libraries,'' he said.

Katherine Martin, president of the Iowa Library Association, said she supports open access to legal information, which includes legal pornography, so long as other library patrons are protected from seeing it.

About 14 percent of Iowa's 543 public libraries and 26 branches use filters, according to a 2004 survey by the Information Use Management and Policy Institute. The survey said about 77 percent do not filter at all, while 7 percent use a blanket filter for all computers in the library.

Nationally, 52 percent of libraries do not filter Internet-ready computers. About 17 percent filter each computer.

In 2003, the U.S. Supreme Court said the federal government can withhold money from public libraries that do not use filtering devices under the Children's Internet Protection Act.

In the Oct. 4 case in Des Moines, Effler allegedly grabbed a 20-month-old girl from the floor near her baby sitter, took her to a restroom and assaulted her. Library workers rescued the girl.

Effler is charged with first-degree kidnapping, second-degree assault and failure to comply with rules of the Iowa Sex Offender Registry because he was not living at the address he listed on the registry.

The Associated Press contributed to this report.