The Fairfax County Board of Supervisors, acting after the second major truck mishap on the Capital Beltway in a month, yesterday called on the Metropolitan Washington Council of Governments to endorse sharp limits on trucks' use of the highway. Some supervisors suggested banning them from the Beltway.

Board members said the move was intended to focus regional attention on the issue of truck safety on the Beltway in order to spur state and federal action to tighten inspections and other safety standards for trucks.

"We're just real little fish in the whole thing," said Supervisor Thomas M. Davis III (R-Mason), referring to Fairfax County's inability to act on its own.

"The only real solution is a regional solution," he added.

On Friday, a tanker truck filled with propane fuel ignited and burned through the afternoon and evening on the Beltway in Prince George's County. On Aug. 12, another tanker truck leaked hazardous chemicals on the Beltway at the height of rush hour in Fairfax County south of Alexandria.

Each incident snarled traffic for miles and forced the evacuation of hundreds of nearby homes.

Several county supervisors suggested yesterday that trucks might be limited to the right lane of the Beltway, banned from the highway or required to use an alternative road, such as U.S. Rte. 301, which runs through eastern Virginia to Baltimore, skirting Washington to the east.

Those actions are beyond the power of the local jurisdictions, however, and would require state and federal actions.

"How many more of these [Beltway] mishaps do we need before we wake up?" County Board Chairman John F. Herrity asked.

He said that referring the safety risks of trucks on the Beltway to COG will alert the area's congressional delegation to the need to take action on the issue.

Supervisor Nancy K. Falck (R-Dranesville), one of the county's representatives to COG, said, "We have to assure [the public] that the Beltway's going to be safe and to at least diminish the odds that something terrible's going to happen."

She said that finding an alternative north-south route, such as Rte. 301, should be a priority. Other supervisors warned, however, that shifting truck traffic to an alternative route might simply transfer the problem, albeit to a less-congested road.

Board Vice Chairman Martha V. Pennino, also a county representative to COG, said COG should devise a plan to restrict trucks' use of the Beltway by limiting the hours they could travel the road, the lanes they could use or the types of cargo they could carry.

In other actions yesterday, the board:

*Voted 5 to 4 to permit the use of credit cards to pay taxes, beginning next year.

*Put off until next week a vote on whether to send a list of questions to Virginia officials on operations and security procedures at the state-run Camp 30 prison in western Fairfax County.

*Formed a subcommittee to check reports that the county is in some instances taking more than a month to deposit personal property tax payments.