Consumers Union is differing with the Consumer Product Safety Commission staff by finding that, despite technological improvements, some new kerosene heaters still pose an indoor pollution hazard.

Publication of an article in the February issue of Consumer Reports, comes just weeks after the CPSC staff reported that a new type of kerosene heater dramatically reduces dangerous air pollutants.

Although CU researchers agreed that the new heaters, Toyostoves, are a substantial improvement over older-style kerosene heaters, they said that on certain settings the heaters still produce "unreasonably high levels of pollutants.

"We have yet to see a kerosene heater that burns cleanly enough to ease our concern about indoor air pollution," Consumer Reports said.

The CPSC said earlier this month that Toyostoves, which are manufactured by Toyotomi America Inc., had achieved a "technological breakthrough" in safety, reducing certain hazardous air pollutants by between 50 percent and 90 percent. Sandra Eberle of the commission's chemical hazards program hailed the heaters as a "dramatic advance."

But Consumer Reports said that the new heaters -- Toyostove DC-100 and Toyostove DR-86 -- can "still produce worrisome levels of pollutants, especially the DC-100 at low-heat settings."

Eberle said that although both organizations tested the heaters in the same manner, the CPSC used the results in different ways to predict consumer exposure.

"They use different modeling assumptions than we do, and in terms of the temperature in the room they don't realistically portray actual consumer use," Eberle said. "They didn't account for the heat buildup that would occur if you use a heater in a closed room. If you turned the heater on to the levels they used, it would get too hot and a consumer would have to turn it down. We take that into consideration."

But David Pittle, technical director of CU, said temperature was taken into account.