The Fairfax County Board of Supervisors this week sharply criticized an annexation bill approved by the Virginia House of Delegates and vowed to conduct an extensive lobbying effort in the Senate to prevent the measure from being enacted.

The bill, which one supervisor described as "the most disastrous piece" of legislation to affect Fairfax County in recent years, could force Fairfax County to share its tax revenues with the surrounding cities of Falls Church, Alexandria and Fairfax.

However, if the county decided against sharing its tax dollars with adjacent cities, the supervisors said, portions of the county could be annexed.

The controversial annexation bill would end the current moratorium on the creation of new towns and set guidelines for towns becoming cities and for cities annexing parts of counties.

"I can't condone any part of this bill," said Supervisor Alan H. Magazine (D-Mason). He said the measure would creat "proliferation of governments. It's certainly going to help some cities and towns."

Board Chariman John F. Herrity, who referred to the annexation legislation as "the ripoff bill," said he is opposed to the county jurisdictions in order to become immune from annexation. "It will seriously impact Fairfax County," he said.

Counties that seek immunity from annexation would have to share revenues based on a complex formula. It is not known how much money such an agreement in Northern Virginia would involve.

Supervisor Martha V. Pennino said she thinks the state has gone obligation to help financially troubled cities. However, she said the counties shouldn't be forced to fulfill that obligation.

The supervisors voiced concern that parts of the county may be annexed by surrounding cities.

Herrity said he thinks Fairfax City may want to annex a portion of the county near 1-66 in an effort to capture the sales and property tax revenues of a major shopping center planned there.

However, Fairfax City officials have repeatedly denied that they are considering such an annexation.

One county official said Fairfax County would be "in a Swiss cheese posture" with the surrounding cities of Fairfax, Falls Church and Alexandria "eating away" at portions of the country.

I Fairfax County were to seek immunity from annexation, it could, under the bill's provisions, block the formation of new towns in the county, such as one often discussed for the Reston community near, Dulles Airport. However, the bill's provisions would not block any existing town in the county such as Vienna, from later seeking city status.

Some communities within the county occasionally have discussed becoming incorporated towns since they feel they can provide better services for their community than services provided by the county.