The developer and builders of Clarksburg Town Center delivered a withering attack on the Montgomery County Planning Board yesterday, charging that the industry has been unfairly blamed for the county government's own failing.

During the latest in a series of hearings on allegations that they violated binding agreements on how the community should have been built, attorneys for Newland Communities and five builders said they were working within the system that the county established -- one that allowed staff members great latitude in approving changes to established plans.

"I have no regrets over or apologies for the actions we have taken in Clarksburg," said Tom Bozzuto, a founding partner of Bozzuto Homes Inc. "We had your approval to build what we did. To say to us now we should not have relied on approved plans sends a chilling message."

Newland and the builders also questioned the legitimacy of the board's investigation, one that involves probing the actions of its staff.

"When the commission's own staff is so directly involved in all the questioned actions, how can this board be impartial?" asked Douglas C. Delano, a Newland vice president.

At one point yesterday, an attorney for one of the builders accused the planning agency of turning its back on a former employee at the heart of the controversy. Wynn Witthans, who managed the Clarksburg project for the agency, resigned in June after acknowledging that she made changes to site plans for Clarksburg so that they conformed with other documents relating to the project.

Kevin P. Kennedy, representing NV Homes and Craftstar Homes, demanded that Witthans be called to testify so she could defend herself and back up his claim that she had signed off on nearly everything that was built.

"You have to get Wynn Witthans here," Kennedy said. "She was a good, meticulous, good government employee working for less than she is worth. Now she has been thrown under the bus, for whatever reason."

Derick Berlage, the Planning Board chairman, sparred with Kennedy over the agency's role but later said he would ask Witthans to testify before the hearings end. He added, however, that he does not have subpoena authority. Witthans declined to comment last night.

The comments from Bozzuto, Delano and Kennedy reflect the rancor and frustration surrounding the planned residential community that has triggered broad debate over Montgomery's land use and development policies.

On July 7, the board agreed with the residents that hundreds of homes had been built too tall or close to the street. The board now is trying to decide whether there were violations to approved plans dealing with the style and configuration of the homes and streets and the location of moderately priced units and recreational amenities.

Last week, the residents were given six hours to present their case, which largely centers on how legally binding site plans differ from what is actually on the ground. Sometime in the next few months, the board will decide on penalties against Newland and the builders, which could top $1 million in fines.

They used as the basis for their defense yesterday documents and meeting logs showing that Witthans and other county officials, including Berlage, had signed off on at least some of the changes to the plans sought by the firms.

Stephen Z. Kaufman, an attorney for Newland, also asked that the board seek the testimony of two dozen other county officials he said were involved in decisions relating to Clarksburg.

One commissioner asked Kaufman whether Newland was requesting that the board recuse itself. He said no, which prompted Nancy C. Lineman, the planning spokeswoman, to say later that the company was making "empty accusations." But Kaufman said the recusal question is something the commissioners "should have been asking themselves."