Two local groups have joined nearly a dozen public interest groups nationwide in a lawsuit challenging the U.S. Environmental Protection Agency over exemptions they believe will weaken regulations designed to impose stricter limits on oil refinery emissions.

It was just last September when the same environmental and public health groups celebrated newly adopted EPA regulations on emissions from the South Bay’s six oil refineries and others nationwide.

But on Tuesday, 11 U.S. groups — including two based in Torrance and Wilmington — sued the EPA for inserting what they consider regulatory loopholes for the refineries without public notice or comment.

San Francisco-based nonprofit public interest law firm Earthjustice is seeking to force the EPA to reconsider the rules it argues will expose “communities to unnecessary cancer-causing pollution,” said Emma Cheuse, a staff attorney for the group.

“In finalizing new national standards in December, EPA created hazardous malfunction exemptions that give oil companies one or two free passes to pollute uncontrollably every three years, and a complete pass to pollute whenever they lose power or have some other ‘force majeure’ event,” Cheuse said via email. “We call on EPA to recognize the need to reconsider and remove these harmful exemptions, which were put in place at the last minute without notice and comment.

“Any oil refinery that can’t handle its responsibility to protect local communities at all times just shouldn’t be operating,” Cheuse added. “It’s not fair and not lawful for oil refineries to get special exemptions from important clean-air requirements designed to protect public health.”

Earthjustice alleges the last-minute EPA rule modifications amount to unlawful violations of the Clean Air Act. There was no immediate response from the EPA.

A petition for reconsideration filed against the EPA notes that polluters who use flares or pressure-relief devices to emit unlimited amounts of pollution when the plant malfunctions due to a power outage or equipment problem can avoid any liability for civil penalties.

The South Coast Air Quality Management District collected data on such releases via pressure-relief devices from 2003 to 2006 and found that up to 89 tons a year of volatile organic compounds were emitted.

“One of the ways they release a lot of toxins in the area is by saying they have a malfunction,” said Cynthia Babich, a former lifelong Harbor Gateway resident who moved out of the area five years ago, but still heads up the Torrance-based Del Amo Action Committee.

The grass-roots group largely champions environmental contamination and cleanup issues in an area of 450 homes and 2,000 residents near Superfund sites in a neighborhood bounded by Vermont and Normandie avenues and Torrance and Del Amo boulevards.

The Wilmington group that joined the effort — Coalition for a Safe Environment — could not be reached for comment.

Environmentalists are frustrated by inadequate pollution-control standards for refineries, in part because some of the same groups had to sue the EPA to come up with the new standards for how releases are discharged and monitored in the first place.

Such rules are supposed to be updated every few years, but the EPA was accused of dragging its feet over the revisions.

The lawsuit comes as ExxonMobil informed the AQMD of two unplanned flares that occurred Jan. 23 and this past weekend.

The most recent flaring, which occurred from 3:56 to 11:59 p.m. Saturday, released more than 500 pounds of sulphur oxides and 500,000 cubic feet of vent gases.

The refinery is beginning to restart operations shut down since the plant exploded in February, crippling its ability to make gasoline, sending pump prices soaring and setting off a series of state and federal investigations over refinery issues that is still ongoing.