TORONTO - A Toronto law firm says a class action suit has been started on behalf of infants who allegedly ingested "potentially lethal components" of Tylenol 3 through breast milk.

The law firm Rochon Genova said the claim was filed April 30 in the Ontario Superior Court of Justice. Janssen-Ortho Inc. and Johnson & Johnson Corp., which make health care products, are named as defendants.

Lawyer Joel Rochon said he's preparing the case for certification.

The claim alleges the companies knew or ought to have known of what it says are serious risks to infants related to the use of Tylenol 3 by nursing mothers, but failed to warn them of those risks.

Rochon said one of the proposed representative plaintiffs is Rani Jamieson of Toronto, whose son Tariq died April 30, 2005, when he was 12 days old.

Allegations in the claim have not been proven in court.

When asked for comment, Janssen-Ortho provided a written statement.

"At this time, we have not had the opportunity to review the claim in full. It has not been served on our company. Tylenol 3 (prescription Tylenol with codeine) is a safe and effective product when used according to the approved prescribing information."