delivered the opinion of the Court.
This case raises the question whether a plaintiff may bring separate actions for separate latent occupational diseases caused by exposure to asbestos. Specifically, we must decide whether the single action rule or the statute of limitations bars Henry Pustejovsky, who settled an asbestosis suit with one defendant in 1982, from bringing suit against different defendants twelve years later for asbestos-related cancer. The trial court granted summary judgment for the defendants based on limitations. The court of appeals affirmed, holding that under the single action rule, Pustejovsky⅛ cause of action for cancer accrued, and limitations began to run, when he knew of the asbestosis.
I
Henry J. Pustejovsky, Jr. was exposed to asbestos from 1954 to 1979 while employed as a metal pourer with Alcoa Aluminum in Rockdale, Texas. In the late 1970s or early 1980s, Pustejovsky learned from co-workers that exposure to asbestos could be harmful. In 1982, Pustejovsky *645 consulted an attorney, who arranged for a doctor to examine Pustejovsky to determine whether exposure to asbestos fibers at work had affected his health. The doctor found scarring on Pustejovsky’s lungs and diagnosed him with asbestosis, a nonmalignant disease caused by inhaling asbestos fibers. The doctor also informed him that the asbestosis resulted from his years of working around asbestos products. In 1982, Pustejovsky sued Johns-Manville Corporation, an asbestos supplier, for damages related to his asbestosis. That suit was promptly settled out of court for approximately $25,000.
In 1994, when Pustejovsky was 59 years old, he began experiencing shortness of breath, cold-like symptoms, and fatigue. In September of that year, a doctor examined Pustejovsky and diagnosed him with malignant pleural mesothelioma, a cancerous tumor of the lung lining. Two months later, Pustejovsky joined with three other plaintiffs and sued Rapid American Corporation, Owens Corning Fiberglas Corporation (Owens Corning), Pittsburgh Corning Corporation, and other suppliers of asbestos products. These four plaintiffs sought damages for their injuries caused by exposure to asbestos. In May 1995, Pittsburgh Corning filed a motion for summary judgment, asserting that Pustejovsky’s claim is barred by the statute of limitations, which began to run for all asbestos-related claims, including mesothelioma, when Pus-tejovsky was diagnosed with asbestosis in 1982. Owens Corning and Rapid-American subsequently joined Pittsburgh Coming’s motion.
Pustejovsky contested the motions with undisputed expert medical evidence that mesothelioma and asbestosis are separate conditions resulting from distinct disease processes. Because the conditions are distinct, Pustejovsky argued, limitations for mesothelioma was not triggered by the diagnosis of his asbestosis in 1982. The trial court granted defendants’ motions for summary judgment and severed Pustejov-sky’s claim against defendants on the grounds that the statute of limitations began to ran in 1982, when Pustejovsky discovered his asbestosis.
1
The court of appeals affirmed the summary judgment, holding that Pustejovsky’s second action was barred by the single action rale and the statute of limitations.
Pittsburgh Corning, Owens Corning, and Rapid-American sought review in this Court. Following oral argument and the submission of the case, first Pittsburgh Corning, then Owens Corning, filed for bankruptcy and, after severance, are no longer parties in this appeal. 2
II
The applicable standard of review is whether Rapid American, as the summary-judgment movant, established that there is no genuine issue of material
*646
fact and that it is entitled to judgement as a matter of law on the grounds it set forth in its motion.
See
Tex.R.Civ.P. 166a(c);
Cathey v. Booth,
Pustejovsky pleaded the discovery rule, supported by the affidavit testimony of an expert on the subject of mesothelioma, Dr. James Robb, as well as Pustejovsky’s affidavit and medical records. As Dr. Robb testified, asbestosis is a non-malignant disease caused by inhaling asbestos dust. When inhaled, asbestos fibers may begin a scarring process that destroys air sacs in the lung where oxygen is transferred into the blood. The condition is marked by decreased pulmonary function and lung capacity. Symptoms include shortness of breath, a dry and unproductive cough, and in some cases, weight loss and chest pain. The scarring is progressive and incurable, but it is not always fatal. According to Dr. Robb, the latency period between toxic exposure and manifestation of asbestosis is typically fifteen to twenty-five years.
Dr. Robb testified further that mesothe-lioma is a malignant tumor in the membranes lining the lungs, abdomen, and chest. The cancer is a very painful and severely debilitating disease that almost always causes the victim’s death within seven to fifteen months of diagnosis. The latency period for mesothelioma is generally over fifteen years, averages thirty to forty years, and in some cases can extend as long as seventy years.
Dr. Robb explained that mesothelioma does not have any causal connection to asbestosis. While both diseases are associated with exposure to asbestos, mesothe-lioma is not dependant on a precondition of asbestosis, and asbestosis does not necessarily develop into, or cause the development of, mesothelioma. According to Dr. Robb, approximately fifteen percent of asbestosis victims also contract mesothelio-ma.
See
In his summary judgment response, Pustejovsky argued that because the diseases are separate, distinct conditions, his asbestosis diagnosis could not trigger limitations for a disease that would not manifest for another twelve years. Because he brought suit for mesothelioma in less than a year of its diagnosis, Pustejovsky contends that limitations does not bar his present suit.
The defendants did not offer medical evidence controverting Dr. Robb’s testimony. Rather, Rapid American argues that the fact that asbestosis and mesothelioma are distinct diseases does not matter because both diseases were caused by the same course of exposure to asbestos. Rapid American contends that the single action rule requires that the statute of limitations for all causes of action based on asbestos exposure began to run from the 1982 diagnosis of asbestosis. Therefore, it argues, Pustejovsky’s present claim for mesothelioma is time-barred as a matter of law. Accordingly, we first consider existing jurisprudence about our single action rule.
Ill
The single action rule, also known as the rule against splitting claims, provides a plaintiff one indivisible cause of action for all damages arising from a defendant’s single breach of a legal duty.
See Gideon v. Johns-Manville Sales Corp.,
The reason for the rule lies in the necessity for preventing vexatious and oppressive litigation, and its purpose is accomplished by forbidding the division of a single cause of action so as to maintain several suits when a single suit will suffice.
Eastland County v. Davisson,
[A] cause of action accrues when the plaintiff knows or reasonably should know that he had been legally injured by the alleged wrong, however slightly. The fact that the plaintiffs actual damages may not be fully known until much later does not affect the determination of the accrual date....
Murphy v. Campbell,
Rapid-American contends that Texas courts have already applied the single action rule and the principles reiterated in
Murphy
in asbestos-related cases to bar any second suits. In
Pecorino v. Raymark Indus., Inc.,
the plaintiff filed suit after he was diagnosed with mesothelioma, even though he had previously settled a lawsuit with the same defendant for asbestosis.
The several pleadings of the [plaintiff] are based upon the same exposure and the same years of exposure to asbestos and asbestos-containing products. Under the decisional precedents of our state, one cause of action arose. Hence, this cause of action could not be split for the purpose of recovering additional monetary damages.
Id. at 571.
The Fifth Circuit Court of Appeals also has considered the single action rule in the context of asbestos litigation. In
Gideon v. Johns-Manville Sales Corp.,
the Fifth Circuit rejected a challenge admitting the plaintiffs evidence that he had a greater than fifty percent chance of developing asbestos-related cancer.
[The plaintiffs] injury is ... the inhalation of fibers and the invasion of his body by those fibers, thus causing him physical damage. Under Texas law, therefore, [the plaintiff] has but one cause of action for all the damages caused by the defendants’ legal wrong; the diseases that have developed and *648 will in probability develop are included within this cause of action, for they are but part of the sequence of harms resulting from the alleged breach of legal duty. [He] could not split his cause of action and recover damages for asbestosis, then later sue for damages caused by such other pulmonary disease as might develop, then still later sue for cancer should cancer appear.
Id. at 1137 (footnotes omitted). As the court explained, under Texas law the cause of action arises from the wrongful act itself, and not from the harm it may cause: “The cause of action ‘inheres in the causative aspects of a breach of legal duty, the wrongful act itself, and not in the various forms of harm which result therefrom....’ [A plaintiff] does not have a discrete cause of action for each harm.” Id. at 1136-37.
Shortly after
Gideon,
the Fifth Circuit held in
Graffagnino v. Fibreboard Corp.,
that, under Texas law, exposure to asbestos can give rise to only a single cause of action for all injuries that are caused by such exposure, whether or not all the injuries have become manifest when the cause of action accrues.
Our court has not considered the effect of the single action rule on multiple asbestos-related injuries. Rapid-American argues that we should adopt the reasoning from the federal and state courts of appeals, and apply them to preclude Puste-jovsky’s current action. It argues that Pustejovsky was entitled to one cause of action for the defendants’ single breach of duty. Thus, it contends that Pustejovsky’s single action accrued in 1982 because Pus-tejovsky’s asbestosis put him on notice that he had suffered a work-related injury. Furthermore, relying on Murphy, Rapid American argues that Pustejovsky’s lack of knowledge of the scope of his damages from his exposure to asbestos does not affect the accrual of his cause of action. Following these general rules, Rapid American contends, Pustejovsky’s claims for damages related to mesothelioma accrued in 1982, and therefore, limitations bars his current action.
IV
For several decades, courts have grappled with the problem of applying limitations to toxic exposure diseases with protracted latency periods, particularly when the exposure can cause more than one disease with different latency periods.
See generally, Maskin, et al., Overview and Update of Emerging Damage Theories in Toxic Tort Litigation,
C837 ALI ABA 629, 642-50 (1993). Like the courts in
Pecori-no, Gideon,
and
Graffagnino,
some courts consider the single action rule to be un-malleable and have applied the rule to different diseases caused by the same exposure.
See e.g., Howell v. Celotex Corp.,
A plaintiff suing for asbestosis could join that claim with a claim for the prospect of developing cancer in the future. But the plaintiff can only recover future damages for injury that the plaintiff has a reasonable medical probability of developing.
See Insurance Co. of N. Am. v. Myers,
In part because of the harshness of its application of the single action rule, the court in
Dartez v. Fibreboard Corp.,
opined that Texas courts would permit recovery for the fear of developing cancer in the future.
Dartez,
Most jurisdictions that have considered the question, however, allow separate actions for separate diseases arising from the same exposure to asbestos.
3
An early
*650
case to treat distinct asbestos diseases separately is
Wilson v. Johns-Manville Sales Corp.,
In latent disease cases, [the] community interest would be significantly undermined by a judge-made rule that upon manifestation of any harm, the injured party must then, if ever, sue for all harms the same exposure may (or may not) occasion some time in the future.
I'd. at 119. The court concluded in that case that the plaintiffs asbestosis diagnosis did not start limitations to run on later developing mesothelioma. Id. at 119-20.
Recently, the Wisconsin Supreme Court considered the issue in
Sopha v. OwensCorning Fiberglas,
V
Since the 1980s, when the federal court of appeals in
Gideon, Dartez,
and
Graffag-nino,
and the state court of appeals in
Pecorino
prognosticated how we might rule on applying the single action rule to asbestos litigation, we have considered pertinent issues in two cases that inform our analysis in this case. Most recently, in
Temple-Inland v. Carter,
we held that an individual who has been exposed to asbestos, but has not developed an asbestos-related disease, could not recover mental anguish damages for the reasonable fear of possible future asbestos-related diseases.
In
Childs v. Haussecker,
we held for the first time that the discovery rule applies to
*651
claims for latent occupational diseases.
VI
Pustejovsky asks our court to follow those jurisdictions that treat claims for distinct asbestis diseases as separate causes of action and hold that Pustejov-sky’s asbestosis settlement does not bar his suit for mesothelioma. In considering Pustejovsky’s arguments, we begin by noting, as we did in
Childs,
that it is the Court’s responsibility to determine the accrual date for Pustejovsky’s cause of action for mesothelioma for limitations purposes.
Childs,
As we noted earlier, the single action rule is a species of res judicata. Strictly speaking, res judicata’s policy concerns about protecting a defendant from multiple litigation are not present here because none of the parties Pustejovsky sued for his mesothelioma were parties to the suit and settlement of his asbestosis claim with Johns Manville Corporation. Res judicata does not apply without an identity of parties or those in privity with them.
See Amstadt v. U.S. Brass Corp.,
A single action rule for separate latent occupational diseases in this context would be incompatible with the “transactional” approach for res judicata that we established in
Barr v. Resolution Trust Corp.,
We have held that a cause of action generally accrues upon injury even if the fact of injury is not known, or not all of the resulting damages have yet occurred.
Murphy,
In the typical case involving progressive injuries, the single action rule may occasionally result in uncompensated damages, in order to vindicate other competing interests. But in asbestos-related cases, in which multiple, latent injuries may manifest years or even decades apart, the rule would produce much more erratic results. The summary judgment record reveals that no amount of due diligence would have allowed Pustejovsky to recover for mesothelioma when he brought his suit for asbestosis. It is our long-established rule that a plaintiff may recover damages for a disease that may develop in future years only if the person establishes that there is a reasonable medical probability that the disease will appear.
See Insurance Co. of N. Am. v. Myers,
Texas would permit a plaintiff to recover damages for a disease that may develop in future years only if he introduces expert testimony establishing that there is a reasonable medical probability that the disease will appear. “Possibility alone cannot serve as the basis for recovery, for mere possibility does not meet the preponderance of the evidence standard. Certainty, however, is not required: the plaintiff need demonstrate only that the event is more likely to occur than not ”
Dartez,
Next, the concerns that warranted the particularized discovery rule for latent occupational diseases in
Childs
are similar to the concerns here that militate for apply-
*653
mg a separate injury rule for each distinct disease process. In
Childs,
we observed that, unlike the typical tort for traumatic injury, the prolonged latency period for some occupational diseases prevents a plaintiff from knowing immediately upon exposure whether they will contract the associated disease.
Childs,
Allowing separate limitations for separate disease processes does not betray the purposes that limitations and the single action rule serve. Like statutes of limitations, the single action rule is intended to discourage stale and fraudulent claims. See id. at 38-39. But evidence about the litigation’s crucial issue, whether the plaintiff actually has mesothelioma, only improves as the disease progresses from asymptomatic to diagnosable. See id. If limitations for an asbestos-related malignancy runs from the discovery of the cancer then damages are tried for an existing, diagnosable disease instead of for the risk or fear of cancer.
The single action rule, like limitations and res judicata, serves the purpose of giving defendants a point of repose. However, a defendant is in no different position with respect to an asbestosis plaintiff who may develop mesothelioma in the future than with an individual who contracts mesothelioma without ever suffering asbestosis. And the defendant’s need for repose must be balanced against the plaintiffs need of an opportunity to seek redress for the gravest injuries, those culminating in wrongful death.
An additional policy reason for the single action rule is the need to protect defendants from vexatious, piecemeal litigation and provide judicial economy. But having to defend against the potential for cancer in every asbestosis case, if we were to allow such a claim, is arguably more vexatious and judicially inefficient than allowing a separate action for actual cancer cases.
VII
After considering the interests underlying the statute of limitations, the discovery rule, and the single action rule, we conclude that the prior asbestosis settlement does not bar Pustejovsky’s suit for mesothelioma. We hold that a person who sues on or settles a claim for a non-malignant asbestos-related disease with one defendant is not precluded from a subsequent action against another defendant for a distinct malignant asbestos-related condition. The diagnosis of a malignant asbestos-related condition creates a new cause of action, and the statute of limitations governing the malignant asbestos-related condition begins when a plaintiffs symptoms manifest themselves to a degree or for a duration that would put a reasonable person on notice that he or she suffers from some injury and he or she knows, or with reasonable diligence should know, that the malignant asbestos-related condition is likely work-related. We decline to follow Gideon, Dartez, and Graffagnino here, and we disapprove of Pecorino to the extent it holds to the contrary.
We limit our holding to asbestos-related diseases resulting from workplace exposure for several reasons. We have considered on other occasions arguments that established doctrine and procedures must change to accommodate asbestos litigation, and on some occasions made those changes.
See, e.g., Owens-Corning v. Carter,
* * *
For these reasons, we conclude that Pustejovsky’s evidence created a question of fact precluding summary judgment on the grounds of limitations. Accordingly, we reverse the court of appeals’ judgment and remand the cause to the trial court for further proceedings.
Notes
. Pustejovsky died during the course of the litigation, and his wife, Joe Ann, substituted as a plaintiff, individually and as representative of her husband’s estate.
. The bankruptcy stays abated any action by this Court. See Tex.R.App P. 8.2. We granted unopposed motions to sever Pittsburgh Coming Corporation and Owens Corning Fiberglas Corporation and reinstate this cause against Rapid American Corporation under Texas Rule of Appellate Procedure 8.3. The cause Pustejovsky v. Pittsburgh Corning Corporation, under the new cause number 00-0561, and Pustejovsky v. Owens-Corning Fiberglas Corporation, under the new cause number 00-1181, remain abated while the automatic bankruptcy stays are in place.
.
See Hamilton v. Asbestos Corp.,
