A party seeking leave to add a defendant beyond the limitation date may do so on the established common law principle of discoverability. This is codified in section 5(1) of the Limitations Act, 2002. The moving party must demonstrate that the limitation period was delayed because they did not know, nor could they have known, through due diligence, about the proposed defendant earlier. The threshold is not a high one.
Although the Court must examine the evidentiary record, where a plaintiff swears they did not know, and could not by due diligence have known, about the proposed defendant prior to the limitation date, a determination may hinge on issues of fact or credibility. In such a case, the proposed defendant can be added (without prejudice to that defendant to raise a limitation defence) as the matter is therefore properly to be determined at trial (or on summary judgment motion).
On the other hand, if it is established that this is a clear case where the moving party knew or ought to have known about the proposed defendant prior to the expiry of the limitation date, with no underlying issues of fact or credibility, then the motion must be dismissed.
A) The Doctrine of Discoverability
The limitation period starts when the cause of action is discovered. The doctrine is sometimes applied in seeking leave to add a defendant when the limitation period would otherwise have expired. The discoverability principle is described by Court of Appeal Justice Borins, who stated:
[T]his principle provides that a cause of action arises for the purposes of a limitation period when the material facts on which it is based have been discovered, or ought to have been discovered by the plaintiff by the exercise of reasonable diligence.
Discoverability is equally applicable to identifying the tortfeasor as it is to discovery of damages. This principle is distinguishable from cases where an unknown party is named in an action (i.e. John Doe) where the party is added by “correcting the misnomer”, in which case the limitation period does not bar the substitution (also circumstance specific).
With respect to discovery of damages, it is possible that damages may not be initially apparent. Take for example, the statutory deductible for non-pecuniary damages in Ontario that must be met in motor vehicle accident litigation, without which no cause of action is deemed to exist. At the Supreme Court of Canada in Peixeiro v. Haberman Major J explained that, “[u]nder the no-fault system in place at the time of the accident, the mere happening of an injury in a car accident does not found a cause of action. No cause of action exists until sufficient severity of injury exists.” Therefore, given that the limitation period is not triggered until the cause of action materializes, this date may not always be readily discernable.
This could provide sound justification for not commencing an action within two years of the date of loss in motor vehicle accident cases where the deductible is clearly not met. This issue was addressed before the Ontario Court of Appeal in Everding v. Skrijel where the cause of action from a collision that occurred in 2000 did not crystallize until an MRI provided objective proof of permanent damage in 2006. An action was commenced in 2007 and the Court of Appeal agreed that the limitation date had not been missed in light of the discoverability.
Similar circumstances were addressed more recently in Pereira v. Contardo, where Justice Perell in the Divisional Court agreed with the decision made by Justice Belobaba in finding that the plaintiff “did not fail to exercise reasonable diligence in discovering that his chronic pain claim might meet the seriousness threshold for a tort claim established by s. 267.5(5) of the Insurance Act, R.S.O. 1990, c. I.8.”
Justice Major in Peixeiro v. Haberman succinctly articulated the natural justice underlying the discoverability principle explaining that it “applies to avoid the injustice of precluding an action before the person is able to sue.”
B) Adding a Defendant under the Doctrine of Discoverability
- The Discoverability Test
In Wong v. Adler, Master Dash relied on the Court of Appeal decision Zapfe v. Barnes, in dismissing a motion to add defendants after expiry of the limitation period. This decision was later upheld on appeal before Carnwath J, in the Divisional Court.
Pursuant to Wong v. Adler, the moving party will be granted leave to add the proposed defendant if they can demonstrate that they did not know, and could not have known, by due diligence, about that defendant earlier. Where determining due diligence hinges on issues of fact or credibility, the motion should be granted and the defendant added because the matter is such that it must be determined at trial (or on summary judgment motion). On the other hand, if the moving party fails to show that they could not have known, through due diligence, about the defendant earlier, then that knowledge may be imputed to them and the motion will be dismissed.
Master Arrell in Ladd v. Brantford General Hospital observed that the plaintiff has the onus of convincing the court, under s. 5(2) of the Limitations Act, 2002, that the date of discovery of the cause of action was at a date other than, in that case, the date of the transfusion.
On the other hand, where the limitation period has expired, the plaintiff may plead special circumstances and no prejudice, which is not detailed here (although this argument tends to be proposed “in the alternative”). Master Dash in Wakelin explained that, “if the limitation period has not expired because of reliance on discoverability, there is no need for the court to consider special circumstances.”
2. The Plaintiff’s Due Diligence
The doctrine of discoverability is not to provide means to remedy a lawyer’s negligence by adding a defendant beyond the limitation period when due diligence would have accomplished the same within limitation period. In Wakelin v. Gourley, Master Dash warned against “rubber stamping” this type of motion where in fact it is the lawyer’s own negligence, caused by a failure to act in due diligence, that lead to the need for the motion.
Specifically, the moving party must show that they had not discovered the relevant facts or identity of the proposed defendant(s) earlier, and that, by due diligence, they could not have discovered the information earlier.
In Zapfe, Court of Appeal explained that the plaintiff would be expected to provide “a list of the attempts made by the solicitor to obtain information to substantiate the assertion that the party was reasonably diligent,” as well as “an explanation for why she was unable to determine the facts.” The motions judge/master is then responsible for assessing “evidentiary record before him in the context of the discoverability principle.”
Master Dash explained that evidence must be “proffered to substantiate the reality that the necessary information had not been and could not with due diligence have been discovered [earlier].” Court of Appeal Justice Lang, in the unanimous decision of Pepper v. Zellers, specified that the plaintiff’s role in establishing discoverability applies both to facts and the tortfeasor’s identity.
Furthermore, Lang J articulated the plaintiff’s positive role in exercising the reasonable due diligence:
The first question in this case related to discoverability, a principle that provides that a limitation period commences when the plaintiff discovers the underlying material facts or, alternatively, when the plaintiff ought to have discovered those facts by the exercise of reasonable diligence. This principle ensures that a person is not unjustly precluded from litigation before he or she has the information to commence an action provided that the person can demonstrate he or she exercised reasonable or due diligence to discover the information. See Peixeiro v. Haberman,  3 S.C.R. 549,  S.C.J. No. 31. The obligation on a plaintiff to exercise reasonable diligence is a positive one: see Soper v. Southcott (1998), 39 O.R. (3d) 737,  O.J. No. 2799 (C.A.).
Therefore, where due diligence has not been established, the court will not be receptive to granting a motion to add a defendant beyond the limitation date.
Wakelin v. Gourley, for example, is a case involving a motor vehicle accident where a passenger initially sued only the driver of the vehicle she was in. The plaintiff moved to add further defendants which it held it could not have known about, by exercise of due diligence, at an earlier date. The inaction of plaintiff’s counsel in investigating this action (for example in failing to obtain the police report in a timely manner) presented a sordid history not lightly treated by Master Dash. Master Dash rejected plaintiff’s argument and dismissed the motion. It is interesting to note Master Dash’s agreement with opposing counsel:
The solicitor for the third party Lisi is correct when she argues that this is the rare case where the addition of a defendant should be denied based on clear and uncontradicted evidence that the plaintiff could have obtained the requisite information prior to the expiry of the limitation period with due diligence. There has been no issue of fact or credibility raised to leave for a trial or summary judgment motion.
In Wakelin v. Gourley the Court emphasized that the moving party must demonstrate the exercise of due diligence or risk losing the motion, stating:
If the plaintiff fails to provide any reasonable explanation that could on a generous reading amount to due diligence the motion will be denied. If the plaintiff puts in evidence of steps taken but the proposed defendant also provides evidence of further reasonable steps that the plaintiff could have taken to ascertain the information within the limitation period then the court will have to consider whether the plaintiff’s explanation clearly does not amount to due diligence. If there is any doubt whether the steps taken by the plaintiff could not amount to due diligence then this is an issue that must be resolved on a full evidentiary record at trial or on summary judgment. The strength of the plaintiff’s case on due diligence and the opinion of the master or judge hearing the motion whether the plaintiff will succeed at trial on the limitations issue is of little or no concern on the motion to add the defendants. The only concern is whether a reasonable explanation as to due diligence has been provided such as to raise a triable issue.
In contrast, therefore, for the responding party, submissions to demonstrate the reasonable exercise of due diligence must be countered because uncontradicted evidence can result in the motion succeeding.
One such case, where the plaintiff’s evidence was not countered, was Zapfe v. Barnes. Master Dash in Wong v. Adler cited Zapfe observing that in that case, opposing counsel did not challenge the plaintiff’s claims that it could not have known the identity of the proposed defendants earlier, and this was a fact which hindered the court’s ability to determine if the plaintiff was reasonably diligent. This in turn, was material in allowing the defendants to be added. Master Dash summarized the Zapfe decision, stating:
It held that the municipalities should be added and the determination of discoverability await a summary judgment motion or trial because the plaintiff’s allegations supported due diligence and were uncontradicted. [emphasis mine]
As the above highlights, opposing the motion becomes especially pertinent in light of the fact that the plaintiffs do not have to meet a high threshold. Master Dash explains:
[A]s long as the plaintiff puts in evidence as to steps taken to ascertain the identity of the tortfeasors and gives a reasonable explanation on proper evidence as to why such information was not obtainable with due diligence then that will be the end of the enquiry and the defendants will normally be added with leave to plead a limitations defence.
3. Issues of Fact or Credibility
As mentioned, if there is a question as to fact or credibility, such as where the plaintiff swears they did not know about the potential defendant, then the issue is properly determined at trial (or summary judgement motion) and the parties may be added notwithstanding their right to bring a limitation defence.
However, Master Dash explained that the Court must review the evidentiary record in determining if there is a basis for a claim of discoverability which would extend the limitation date, otherwise, the court is at risk of “rubbing stamping” the addition of defendants, possibly even in the face of solicitor negligence.
In a motion that succeeded on issues of fact and credibility, in Ladd v. Brantford General Hospital, the plaintiff sought leave to add Canadian Blood Services (CBS) as a defendant in a tainted blood action. Plaintiff’s counsel had in their possession hospital records which did not indicate anywhere that the blood was received already tainted. Presumably, if it had, it would have become clear that CBS was the last source to screen the blood and as such was a potential defendant. In Ladd, the material information was not clear cut and due diligence was a valid issue hinging on issues of fact or credibility. Therefore, pursuant to Wong v. Adler, the motion was successful.
- Imputed Knowledge
Where information pertaining to the proposed defendant is in the possession of the moving party early on, knowledge of the claim against the proposed defendant may be imputed to the moving party. In Wong v Adler the plaintiff claimed that “she did not know and could not reasonably have known the identity of the tortfeasor Olivieri until May 14, 2003, when Adler’s statement of defence named Olivieri as the responsible party.”
Master Dash has indicated that the amount of evidence required by the plaintiff in establishing that “the proposed defendants could not have been identified with due diligence within the limitation period… is: not very much.”
Even though plaintiff’s counsel submitted that it was not aware of the information, the court imputed the knowledge to them given that the information was shown to have been present in their file.
In conclusion, as a precautionary measure, careful steps should be taken by plaintiff’s counsel to exercise due diligence in discerning the cause of action and limitation period including maintaining a record of all steps taken to fully investigate the action, and in particular, the cause of action. Where an obvious limitation period will expire without the commencement of a lawsuit, a careful analysis should be undertaken, including full disclosure to the plaintiff who may lose their right to pursue the action in tort, not to mention obtaining written instructions.
 Limitations Act, 2002, c. 24, Sched. B, s. 5 (1), see also section 4.
 Limitations Act, 2002, c. 24, Sched. B, ss. 4 and 5 (1)(a)(iii); Wong v. Adler, 70 O.R. (3d) 460,  O.J. No. 1575 at para 25; Aguonie v. Galion Solid Waste Material Inc., (1998), 38 O.R. (3d) 161, 156 D.L.R. (4th) 222 at para 24 (C.A.) (Canlii); Peixeiro v. Haberman,  3 S.C.R. 549, 151 D.L.R. (4th) 429, at para 44.
 Wakelin v. Gourley,  O.J. No. 2746, 76 O.R. (3d) 272,  O.T.C. 572 at para 15 [Wakelin].
 Wong v. Adler, 70 O.R. (3d) 460,  O.J. No. 1575 at para 45 [Wong].
 Ladd v. Brantford General Hospital,  O.J. No. 4199, 88 O.R. (3d) 124 at para 17 [Ladd].
 Wong supra note 4 at para 45.
 Aguonie v. Galion Solid Waste Material Inc., (1998), 38 O.R. (3d) 161, 156 D.L.R. (4th) 222 at para 24 (C.A.) (Canlii).
 Wong v. Sherman,  O.J. No. 1534 (Gen. Div.) at para. 28, quoted in Wong, supra note 6 at para 28.
 Spirito v. Trillium Health Centre,  O.J. No. 4524, 2008 ONCA 762.
 Peixeiro v. Haberman,  3 S.C.R. 549, 151 D.L.R. (4th) 429, at para 30.
 Everding v. Skrijel,  O.J. No. 2534, 2010 ONCA 437.
 Pereira v. Contardo, 2014 ONSC 6894 (Canlii).
 Peixeiro v. Haberman,  3 S.C.R. 549, 151 D.L.R. (4th) 429, at para 44.
 Wong, supra note 4.
 Zapfe v. Barnes, 66 O.R. (3d) 397,  O.J. No. 2856, 2003 CanLII 52159.
 Wong v. Adler,  O.J. No. 1400, 76 O.R. (3d) 237, 17 C.P.C. (6th) 65.
 Limitations Act, 2002, S.O. 2002, Ch. 24, s. 5(2).
 Ladd, supra note 7 at para 14.
 The doctrine of special circumstances is an entire subject on its own.
 Wakelin, supra note 3 at para 3.
 Wong, supra note 4 at para 46; Wakelin, supra note 3 at para 27.
 Wakelin, supra note 3 at para 27.
 Zapfe, supra note 13 at para 35.
 Ibid., at para 34.
 Ibid., at para 31.
 Wakelin , supra note 3 at para 5.
 Pepper et al. v. Zellers Inc. c.o.b. Zellers Pharmacy,  83 O.R. (3d) 648 at para 17 [Pepper v. Zellers].
 Ibid., at para 16.
 Wakelin, supra note 3 at para 27.
 Ibid., at para 15.
 Wong, supra note 4 at para 39.
 Wakelin, supra note 3 at para 15.
 Wong , supra note 4 at para 45.
 Ladd, supra note 7 at para 17.
 Wong, supra note 4 at para 27.
 Wakelin, supra note 3 at para 14.