Proponents have voiced concern that the city will be a dumping ground for higher-sulfur fuel as lower limits take effect outside Philadelphia - in New Jersey, Delaware, and the rest of Pennsylvania.
Most homes in the city are heated by natural gas, according to U.S. Census data. About 6 percent - more than 36,000 homes - use heating oil, as do some smaller businesses.
Sulfur is a component of crude oil that, when burned, releases sulfur dioxide. Even short-term exposures can exacerbate asthma and other respiratory ailments.
Further, sulfur dioxide contributes to the formation of fine particulate matter, which travels deep into the lungs, where it can be absorbed into the bloodstream. With other pollutants often attached, particulates can worsen not only respiratory diseases but also heart disease, leading to heart attacks. Philadelphia does not meet national air-quality standards for particulates.
Most sulfur dioxide emissions, by far, come not from home furnace flues, but from power-plant smokestacks. Still, many states in the Northeast, which uses 80 percent of the nation's heating oil, have seen limiting sulfur in heating oil as one more way to address sulfur dioxide pollution.
Noting that 22 percent of Philadelphia's children have asthma, Nan Feyler, city public health department chief of staff, said lower sulfur standards are "really necessary."
Joseph O. Minott, executive director of the Philadelphia-based Clean Air Council, backs the change, calling it "high time."
Pennsylvania has a statewide standard, currently 2,000 to 3,000 parts per million of sulfur, but it is being lowered to 500 ppm by July 2016. Because Philadelphia is so large, the state gave it the authority to develop its own air quality program.
Philadelphia's standard, passed in 1978, is 2,000 ppm. Reynolds Brown has proposed 15 ppm by July 2015, matching "ultra-low" sulfur fuel standards to go into effect in New Jersey, Delaware, and New York by July 2016.
"The residents of Philadelphia deserve no less," Minott said.
Earlier this year, Reynolds Brown proposed allowing the city's Air Management Services - which monitors air pollution and enforces city, state, and federal regulations - to set sulfur limits. A hearing on the bill drew officials of South Philadelphia's refinery, Philadelphia Energy Solutions (PES).
Sulfur can be removed from the oil during the refining process, but that requires special equipment.
At the hearing, Mark Brandon, an optimization director at PES, testified that the refinery currently meets the 15 ppm standard for most of the home heating oil it produces. However, he said, that standard is not met when equipment must be shut down for repairs.
When that happens, "we do look for markets where we can, for a short duration . . . move that product favorably and economically," he said. "Sometimes, that's locally."
Otherwise, he said, "we would have to seek out ways to either shrink our capacity during those times, at great cost, or store at great cost the product up to a million barrels at a time . . . then reprocess it through the facility when the equipment is back online."
Later in the hearing, Brandon said that the company would not object to a 15 ppm standard in Philadelphia. "Our objection would be if the result was more strict," he said. "We don't currently have equipment that can meet stricter standards."
A PES spokeswoman declined to comment on the new proposal or to elaborate on the earlier testimony, ahead of Wednesday's hearing.
"What's frustrating to me is, no one is arguing they can't do it from a technological point of view. They can," Minott said. ". . . But when [their] equipment is down, [they] want to sell the more polluted material because [they] want to make money."
Reynolds Brown also proposed lower sulfur limits for No. 4 oil, used in some commercial burners.
Based on an analysis of several reports, officials at Air Management Services estimate lower-sulfur fuel could save 11 lives a year in the city, and prevent hospitalizations and emergency room visits, as well as reduce absenteeism and health-care costs.
Lower sulfur content also makes for a cleaner, more efficient fuel, extending a furnace's life span and saving customers money on maintenance, said Roy Patterson, executive vice president of the Delaware Valley Fuel Dealers Association.
However, some of the savings could be offset by higher fuel costs that may be associated with the added refining process.