Members of the Arlington County Board, concerned about the conversion of half of Arlington Towers into a much-publicized condominium, are considering adopting some of the most stringent regulations ever imposed on such a project in the county.

Under the proposals, the massive 1,680-unit River Place development overlooking the Potomac River at Rosslyn would be required to reserve additional units for elderly and handicapped residents and submit its security plan to police for review. If the measures are adopted by the board, Arlington would be among the first Virginia localities to implement the provisions of a new state law allowing stricter controls over condominium conversions.

Both Democrats and Republicans on the County Board complained last week that River Place's developers had handled the conversion poorly. "There are some very real problems," board member John G. Milliken, a Democrat, said at a board meeting. "I think there has been some trouble from the beginning of the conversion ."

The board met last week for what was supposed to be a routine review of the River Place developer's plan for continued conversion of about half the units in the project, which has been advertised on television and in newspapers for months. But complaints from angry River Place renters transformed the meeting into a forum for accusations against the developer, Monument Associates. Renters charged that the developers have not maintained adequate security in the buildings and have forced out elderly tenants.

"Now, I'm a retired Army colonel and I don't scare easy," said Hazel Ingersoll, who heads the Arlington Towers' Residents Association, "but walking down that hall at 11 in the night scares me."

Another tenant, Erika Cline, said: "The developers are inflicting great stress and emotional injury on elderly."

One of River Place's developers, Gary Nordheimer, later defended the conversion. "I think we've conducted ourselves very well," he said in an interview.

"For those people who did not want to convert over to ownership ," River Place spokesman Gary Rabin said later, "they were offered the standard 120-day move-out period, and 50 were given extensions." River Place officials said they have paid $122,000 to tenants in relocation assistance, moved many residents to unconverted buildings in the complex, offered large discounts to present renters and improved building security.

The debate reopened controversies the County Board had urged developers to resolve earlier. The discussion led to a proposal by Milliken to require the developers to reserve 20 percent of the building units for present elderly and handicapped residents and to require police to make a comprehensive review of River Place's security plan.

River Place spokesman Rabin said after the meeting that the developers, Nordheimer and his brother, Scott, are willing to accept Milliken's proposal. It will be considered at the County Board's June 22 meeting.

River Place is prepared to set aside 20 percent for the elderly and handicapped, in addition to 60 units already reserved for other existing tenants, Rabin said.

Virginia municipalities have less control over condominium conversions than does the District, although the new law to take effect July 1 allows jurisdictions to mandate a 20 percent set-aside for the elderly and handicapped.

"I can't remember when we've had a site plan when we've struggled so hard," said board member Walter Frankland during the board meeting. He criticized the developers for failing to resolve the problems with the tenants.

Amendments to the River Place site plan, which the County Board must approve, call for improvements to two buildings being converted to condominiums. Changes include building new parking and housing units, adding a shopping village and improving amenities.

The two buildings contain about 800 residential units. Sales contracts with deposits have been received on about 350 units, 58 units have been sold and about 60 units are scheduled to be sold next week, a River Place official said.