Benzene-based consumer class actions are becoming almost routine. So are their dismissals on preemption grounds. It takes something a little different to make one stand out. The plaintiff in Leonard v. CVS Pharmacy, 2026 WL 986311 (N.D. Cal. Apr. 13, 2026), tried just that, invoking a res ipsa loquitur–type theory to plead “parallel” CGMP violations. That move may sound familiar to those who follow medical device litigation, where it has been tried—and rejected—before. But as far as we know, this is the first time plaintiffs have attempted to import that playbook into the growing wave of benzene cases.
It didn’t work here either.
We probably shouldn’t be surprised. This was already plaintiff’s second attempt to bring her consumer protection claims against the manufacturers of generic Mucinex. The court previously dismissed her claims as expressly preempted after concluding that the FDA’s approval of the drug’s ANDA, which disclosed that its manufacturing process involved a carbomer that could introduce benzene, necessarily determined the product complied with the FDCA. Claims that the product was “adulterated” or “misbranded” because it contained benzene imposed requirements different from federal law and were therefore preempted. Id. at *1. Plaintiff was given leave to amend. She did—but not successfully.
Round two swaps out express preemption arguments for a “parallel violation” theory grounded in CGMPs. Plaintiff alleged that defendants violated those regulations and that the violations resulted in benzene contamination. But as the court quickly recognized, the theory had a glaring problem: it was entirely unsupported by facts. Indeed, “the only fact Plaintiff alleges to support her allegations that Defendants violated the cGMPs, is the presence of benzene itself.” Id. at *2. But that’s just circular reasoning.
Start with the basics. CGMPs do not regulate the presence of benzene. In fact, the FDA approved the product with the condition that it could contain benzene below a certain threshold (2 ppm). Id. at *3. So, the mere presence of benzene does not establish a CGMP violation. And if plaintiff’s position is that any benzene violates CGMPs, that would put her theory squarely at odds with the FDA’s approval—creating the very conflict that preemption forbids.
So, plaintiff tried a different tack suggesting that maybe the levels were too high. But here again, the complaint comes up empty. There are no factual allegations about the benzene levels in the product plaintiff actually purchased—only the assertion that benzene levels can be “astronomically high.” Id. But saying something can happen is not the same as alleging that it did happen. Saying a product can contain high levels of benzene is like saying a lottery ticket can be a winner. True—but most aren’t. Plaintiff needs “more than a sheer possibility” to satisfy TwIqbal. She didn’t get there.
Plaintiff also attempted to anchor her claims by listing various CGMPs—written procedures, laboratory controls, recordkeeping obligations. But again, the complaint offered no facts explaining how any of those requirements were actually violated. A laundry list of regulatory provisions, untethered to factual allegations, likewise does not satisfy federal pleadings standards. Again, plaintiff relied exclusively on the presence of benzene as purported proof that defendants violated the CGMPs. But the court was unwilling to take the leap plaintiff invited–to infer that the failure to keep written procedures, laboratory controls, or laboratory records caused the presence of benzene. Id.
That’s where the res ipsa theory ultimately collapses. The premise is that benzene should not be present unless something went wrong, so the court should infer a CGMP violation. But as courts have already recognized in the device context, complex medical products and complex regulatory schemes do not lend themselves to that kind of shortcut. Without factual allegations connecting the dots, there is no “parallel” claim—just speculation dressed up as doctrine.
This time, because plaintiff advanced a new theory, she gets one more chance to try to plead it. But stepping back, the broader takeaway is becoming hard to ignore. Plaintiffs keep looking for a way into these benzene class actions—and keep running headfirst into preemption. Express preemption has blocked one path. Implied preemption has closed off another. And now, even repackaging the claim as a res ipsa-style “parallel violation” theory meets the same fate.
At some point, the pattern matters. Plaintiff may get another opportunity to re-plead in this case, but it is difficult to see what avenue remains. Without facts showing an actual, non-preempted violation tied to her product, simply relabeling the theory is not going to get her over the hump. So far, every path leads back to the same place: dismissal.