Federal putative class action suits are mounting against the maker of an air-pressured toilet system that allegedly explodes under certain conditions.

The Series 503 Flushmate III Pressure-Assist Flushing System was recalled last June, and since then at least five suits have been filed and more are on the way, attorneys say.

The system, which has been fitted into several brands of toilets, uses a pressurized vessel that compresses air as the water tank fills, resulting in a more powerful flush when the air is released. But plaintiffs allege the air vessel tends to separate at its weld seam, causing it to leak or burst. The latter can cause the porcelain tank to shatter or the tank lid to dislodge, which in turn “can lead to substantial property damage as well as serious physical injury, including a risk of laceration,” the plaintiffs claim in the most recent complaint, Brettler v. Flushmate, 12-cv-7077, filed Nov. 14 in Camden.

Flushmate allegedly failed to inform manufacturers and consumers about a history of known failures dating back to at least 2000. Product advisories released in July 2000 and June 2003 warned about possible leaks in some units but failed to explicitly mention explosions, weren’t well circulated and did not convey the severity or scope of the issue, the plaintiffs claim.

Flushmate, of New Hudson, Mich., a division of Franklin Park, Ill.-based Sloan Valve Co., denies the allegations.

There are a total of 2.33 million affected units in the United States and 9,400 in Canada, the plaintiffs say.

Last June 21, the federal Consumer Product Safety Commission — as well as Health Canada, its Canadian counterpart — announced a voluntary recall encompassing units manufactured from Oct. 14, 1997, through Feb. 29, 2008. At the time, the notice said, Flushmate had received 304 reports of explosions, including 14 that caused injuries.

Flushmate warned consumers of possible explosions and advised them immediately to cease using and to cut off water supply to the toilets. The company also offered free repair kits, which many owners have paid plumbers to install. But they don’t fit some toilets and don’t fix the problem, plaintiffs say.

Lead plaintiff Jeffrey Brettler of Pemberton claims he spent $1,500 to buy and install three Gerber toilets equipped with the Flushmate III in March 2007, and later installed the repair kit, but still fears a toilet explosion.

The suit seeks nationwide class certification for all owners of toilets equipped with the Flushmate III made during the period indicated in the recall notice, as well as certification of a New Jersey class.

Putative class members allegedly suffered damages in an amount equal to the difference between market value of the defective toilets and functional toilets, the replacement costs and any costs associated with installation of the repair kit or removal of the Flushmate system.

The plaintiffs urge tolling of the statute of limitations based on fraudulent concealment of the defect.

They assert common-law causes of action; strict liability based on design defect, manufacturing defect and failure to warn; and violations of the state Consumer Fraud Act and federal Magnuson-Moss Warranty Act.

The first complaint against Flushmate was filed on Aug. 9 in the Central District of California, United Desert Charities v. Flushmate, 12-cv-6878. Two others subsequently were filed in other federal courts in California.

Also named as defendants in those suits are toilet manufacturers and a retailer.

Brettler’s lawyer, Jordan Chaikin of Parker Waichman in Bonita Springs, Fla., filed a previous putative class suit on Nov. 2 in the Northern District of Florida, Berube v. Flushmate, 12-cv-531. He says he has as many as six other prospective plaintiffs lined up in different states and anticipates petitioning for consolidation of the matters in multidistrict litigation.

Chaikin says Parker Waichman has been contacted by five to 10 potential plaintiffs injured by flying shards of porcelain, including a man who suffered an eight-inch stomach laceration and a woman who suffered a severed tendon in her big toe. Separate, individual personal-injury suits likely will be filed on their behalf, he says.

The California plaintiffs are represented by David Birka-White, who heads a firm in Danville, Calif. Two of the three suits were dismissed as the parties agreed to centralize the plaintiffs in United Desert Charities, he says. The court ordered the consolidation on Nov. 13.

Both attorneys say that, as of Tuesday, they weren’t aware of any other such suits against Flushmate and hadn’t communicated with each other yet.

Flushmate spokesman Paul DeBoo wrote in an email: “We believe the lawsuit is without merit. We will defend it vigorously.”

Steven Frankel of SNR Denton’s San Francisco office, who is lead defense counsel in the California suits, declines comment.

There have been no defense appearances in the Florida or New Jersey cases and DeBoo would not identify the attorneys retained.