GARDINER, Maine — Bangor Gas representatives report that hundreds of customers are looking into switching their home or business heating system from oil to gas.

But the surging interest in converting oil-fired furnaces has some fire safety officials concerned. So they are asking a state board to clarify codes intended to protect customers from harm and shield installers, inspectors and municipalities from liability.

Jonathan Kunz, manager of marketing and sales at Bangor Gas, estimated that 800 customers in the company’s service area are exploring converting to natural gas because of the high price of oil. Some of those customers would buy new gas furnaces, but many others hope to retrofit oil-fired furnaces using special conversion kits.

There is a serious disagreement, however, among the gas company, Bangor fire officials and state inspectors about who can and should vouch for the safety of these gas conversion burners. While the disagreement apparently hasn’t stopped anyone from converting from oil to gas, it is prompting discussion about who would be liable from a mishap with a retrofitted unit.

“We have been getting a lot of calls on this issue,” Paul Moody, senior inspector for Maine’s Propane and Natural Gas Board, told board members Thursday. “There’s a lot of confusion in the field.”

The issue, according to representatives of both sides, is not necessarily that these oil-to-gas conversion burners are unsafe. Untold numbers of oil boilers have been converted to natural gas over the past several decades in other regions where residential gas lines are readily available.

“There is no safety issue in terms of incidents in the other states that have been doing these for years and years and years,” said Joe Rose, president of the Propane Gas Association of New England.

Instead, the disagreement is over who should certify that the after-market conversion kits are safe to install, especially when many oil-fired boiler manufacturers do not endorse their use. The two sides also interpret language in national codes differently.

“We have manufacturers saying we do not want [their] oil burners converted to gas,” said Dale Hersey, a compliance officer for the board. “The question we have is when can we do this.”

Representatives of Bangor Gas and one conversion burner manufacturer said they believe existing codes are adequate. The manufacturers of the conversion kits are the ones who test and vouch for the safety of the gas burners, not the furnace manufacturer, they said.

As evidence, Kunz and others cited a December 2005 letter from the Gas Appliance and Manufacturers Association stating that no other states require authorization from the boiler manufacturer.

“Requiring the boiler manufacturer’s approval prior to a gas conversion is [hurting] the ability of consumers in Maine to use natural gas for their heating needs,” reads the letter, which was sent to Moody. Bangor Gas had been laying new lines in the Bangor area around the time of the letter.

But Bangor fire officials cite language from a national code system on installation of gas conversion burners — language adopted by the board and cited in the GAMA letter — that states “in no case should the appliance be modified beyond the recommendation of the appliance manufacturer.”

“In my humble opinion, if you are changing from No. 2 [oil] to natural gas, you are modifying the appliance,” Bangor Fire Chief Jeff Cammack said.

Cammack urged the board to clarify the issue.

In the meantime, the city will give homeowners a letter clarifying that their inspectors can certify only that the conversion burner was installed correctly according to the burner’s instructions. Inspectors cannot speak to the conversion unit’s safety or its effects on the boiler.

The board is expected to take the issue up again at its next meeting, scheduled for November.