The fate of an ordinance that could force Chicago’s two coal plants to shut down or convert to natural gas will be left to Mayor-elect Rahm Emanuel’s administration and the new City Council after a vote was put off Thursday at a council committee hearing.

Retiring Ald. Virginia Rugai (19th Ward), the chair of the Energy, Environmental Protection and Public Utilities committee, opened the joint hearing with the announcement that the current council would not vote on the politically-charged Chicago Clean Power Ordinance.

Workers employed by Midwest Generation, the owner of the plants, packed the city council gallery. Most of them were bused in from Midwest Generation’s other Illinois plants; the Chicago plants employ about 185 people, only about a fifth of them Chicago residents, according to the plant manager’s testimony Thursday. Midwest Generation employees periodically cheered and booed loudly throughout the hearing, with Rugai threatening to remove them when the noise interrupted a public health advocate’s testimony six hours into the hearing.

Activists who didn’t get seats protested outside, their chants audible inside the chamber. Proponents of the ordinance have been pushing for a committee hearing since it was introduced a year ago by Ald. Joe Moore (49th). The ordinance has since gained 26 co-sponsors, a slim majority, and supporters were hopeful it would go to a full vote before the new council is seated in May.

Emanuel had said he wants the plants to reduce their emissions in a “Green Growth Platform” pre-election questionnaire issued by a coalition of environmental and planning groups. He did not say on the questionnaire if he would support the ordinance.

The ordinance would force Midwest Generation to slash its emissions of carbon dioxide and particulate matter at the Fisk and Crawford generating stations in Pilsen and Little Village. Midwest Generation spokesman Doug McFarlan told the committee members the ordinance would force the plants to close because meeting the carbon dioxide limit would be possible only by converting to natural gas. He said that would be too expensive.

“It’s a shut down ordinance – you can’t comply with those standards with existing technology,” McFarlan said.

Before the hearing, Ald. Danny Solis (25th) and Moore said they would consider renegotiating the carbon dioxide component of the ordinance in order to make sure the particulate matter provision passes. Particulate matter is linked to elevated risk of cancer, lung disease and heart disease. Carbon dioxide is the major driver of climate change but has no localized health effects.

“If Midwest Generation chooses to comply with this ordinance by shutting down, it is the company making that choice, not city council,” Environmental Law and Policy Center senior attorney Faith Bugel said at the hearing, noting that other coal plants across the country have converted to burning natural gas. “With every environmental regulation, the coal companies have always cried wolf and said it would cause them to shut down.”

McFarlan said the plants could also close if the company decides it is too expensive to install technology necessary to meet the requirements of a 2006 agreement with the Illinois Environmental Protection Agency. That agreement required cuts in sulfur dioxide, nitrogen oxide and mercury emissions. Midwest Generation has already significantly reduced nitrogen oxide and mercury emissions, but meeting the sulfur dioxide requirements by 2018, as per the agreement, could be prohibitively expensive, McFarlan said. The 2006 agreement does not address carbon dioxide.

Moore opened the hearing by telling workers the ordinance would not cause them to lose their jobs. The ordinance mandates retention and retraining plans for any affected workers.

“Not a single job will be affected,” said Moore. “If the plants need to convert, if they undoubtedly need to put in additional pollution control measures, that will create good union jobs. This is not an ordinance only designed to protect jobs, it’s an ordinance designed to create jobs.”

Dean Apple, president of the IBEW Local 15 union that represents workers at the plants, said a conversion to natural gas could potentially lead to job cuts if gas prices go up and the company decides the plants aren’t profitable.

“Gas is very cheap right now, but no one has a crystal ball,” he said. “What will be happening in three years, in five years? I know it’s in their DNA, if things get bad they’ll tear it down.”

Chicago Department of Environment commissioner Suzanne Malec-McKenna said the power plants represent only a small fraction – several percent – of carbon dioxide emissions and particulate matter emissions in the city. Diesel exhaust and dust from construction sites are the largest sources of particulate, and vehicle exhaust is the largest source of carbon dioxide, she said.

Solis, who represents the Pilsen neighborhood where the Fisk Generating Station is located, had not taken a position on the ordinance until after February’s election, when he was forced into a run-off with Cuauhtemoc Morfin, an outspoken critic of the power plants. The Service Employees International Union (SEIU) state council sent out a glossy mailer attacking Solis for failing to back the ordinance. In March, after being endorsed by SEIU, Solis announced his support for the ordinance.

“The voters spoke,” Solis told the Chicago News Cooperative last week. “This is a top priority issue in my ward, and an alderman should listen to his or her constituents. A number of my constituents said they voted for me because they thought I would change my mind, and a number said they voted against me” because he had not backed the ordinance.

After Solis switched his position on the ordinance, his backers circulated a mailer attacking state and federal authorities for what it claimed was a lack of action on the coal plants. In 2009, the U.S. Department of Justice and the state of Illinois sued Midwest Generation for allegedly violating the Clean Air Act.

At the hearing Solis lauded Midwest Generation for reducing sulfur dioxide and nitrogen oxide emissions since purchasing the plants from ComEd in 1999 and he suggested using TIF money to help the company install additional pollution controls.

“Let me tell you this, ComEd was a lot dirtier than Midwest Generation,” Solis said at the hearing. “Midwest Generation did a tremendous job when they took over in making it a lot cleaner than what we had before.”

Solis said his earlier lack of support for the ordinance was because he doubted the city has the legal authority to regulate the plants. Midwest Generation officials have said they will likely sue on those grounds if the ordinance passes, while Moore has said the Home Rule provision in the Illinois constitution gives Chicago the right of enforcement.

At the hearing, Chicago law department senior counsel Ron Jolly said the department would “vigorously” defend the ordinance if it passes, though a previous Illinois Supreme Court decision casts doubt on whether the Home Rule provision can be used for environmental rules.

Solis also pointed out other sources of pollution in Pilsen, including emissions from trains carrying coal and other commodities through the neighborhood. Locomotives are a major source of particulate emissions, as recent testing by the Chicago News Cooperative demonstrated.

Solis asked environment commissioner Malec-McKenna whether the city can force locomotives to reduce idling. She responded the city cannot, since railroads are federally regulated.

“So again we have to go to the federal government to do the jobs we need to do to get a cleaner environment,” Solis said.