231 F.3d 242 (6th Cir. 2000)
Creighton E. Miller, Administrator of the Estates of Juvenal  J. Rezendes, Deceased (99-3703), Louie E. Hudson, Deceased (99-3705), Booker T. Pompey,  Deceased (99-3707), Walter L. Bowman, Deceased  (99-3708), William B. Birch, Jr. (99-3709), Plaintiff-Appellant,v.American Heavy Lift Shipping, et al., Defendants-Appellees.
Nos. 99-3703, 99-3705, 99-3707, 99-3708, 99-3709
UNITED STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT
Argued: June 21, 2000Decided and Filed: November 3, 2000

Appeal from the United States District Court for the Northern District of Ohio at Cleveland.  Nos. 90-10263; 91-10448; 91-10775; 92-10151; 92-10427--John M. Manos, District Judge.[Copyrighted Material Omitted]
John C. Cardello, Donald  A. Krispin, THE JAQUES ADMIRALTY LAW FIRM, Detroit, Michigan, for Appellant.
Harold W. Henderson, Richard  C. Binzley, THOMPSON HINE & FLORY LLP, Cleveland, Ohio, for Defendants-Appellees.
Gene B. George, RAY, ROBINSON, CARLE &  DAVIES, Cleveland, Ohio, for Appellees.
Before: MERRITT, GUY, and COLE, Circuit Judges.
COLE, J., delivered the opinion of the court, in which MERRITT, J., joined. GUY, J. (pp. 252-53), delivered a separate  dissenting opinion.
OPINION
R. GUY COLE, JR., Circuit Judge.


1
Plaintiff-Appellant Creighton E. Miller is the administrator of the estates of five  deceased seamen. In the years 1990-1992, Miller brought five separate actions against various shipowners and operators,  alleging survival and wrongful death claims under the Jones Act, 46 U.S.C. App. § 688, and general admiralty and  maritime law. In 1997, Miller filed amended complaints in each case. The district court found that the amended complaints  did not relate back to the original complaints pursuant to Fed. R. Civ. P. 15(c)(2), and, as such, were barred by the  three-year Jones Act statute of limitations. For the reasons discussed below, we REVERSE the decision of the district court  and REMAND for further proceedings consistent with our opinion.

I. BACKGROUND

2
Miller is the administrator of the estates of Juvenal J. Rezendes, William B. Birch, Jr., Walter L. Bowman, Louie E.  Hudson, and Booker T. Pompey ("the seamen"). Each of the seamen worked for many years on various ships. All the  seamen were diagnosed with leukemia prior to their deaths in 1987, 1988, or 1989. In 1990, 1991, and 1992, Miller brought  suit under the Jones Act, 46 U.S.C. App. § 688,1 and general maritime law against Defendants-Appellees American  Heavy Lift Shipping, et al. (on behalf of Rezendes), American President Lines, Ltd., et al. (on behalf of Birch), Amerada  Hess Corp., et al. (on behalf of Bowman), Alcoa Steamship Company, Inc., et al. (on behalf of Hudson), and Farrell Lines,  Inc. (on behalf of Pompey) (collectively, "Shippers"). See Smith v. Gulf Oil Co., 995 F.2d 638, 642 n.3 (6th Cir. 1993). In  each case, Miller brought suit prior to the running of the Jones Act's three-year statute of limitations. See 46 U.S.C. §App.  688 (incorporating by reference the three-year statute of limitations contained in 45 U.S.C. § 56); Mamer v. Apex R.E. & T., 59 F.3d 780,782 n.2 (8th Cir. 1995). In the complaints, all of which were substantively identical (only the headers and  named defendants differed), Miller raised both survival and wrongful death actions, based on theories including negligence  and breach of duty to maintain a safe and seaworthy vessel. Miller alleged that the seamen had sustained injuries as a result  of their exposure to asbestos and to hazardous substances other than asbestos while working as seamen. In particular, the  relevant language of each complaint reads as follows:


3
10. While serving as a mariner on said vessels, Plaintiff's decedent was exposed to hazardous substances other than  asbestos.


4
11. As a direct and proximate consequence of his exposure to hazardous substances other than asbestos, Plaintiff's  decedent has sustained injuries....


5
Later in each complaint, Miller further stated:


6
16. While serving as a mariner on said vessels, Plaintiff's decedent was exposed to asbestos and hazardous substances  other than asbestos.


7
17. As a direct and proximate consequence of Plaintiff's decedent['s] combined exposure to asbestos and hazardous  substances other than asbestos, Plaintiff's decedent has sustained injuries.


8
In response to numerous asbestos-related personal injury actions filed by seamen in the Northern District of Ohio, the  court created a special Ohio Maritime Asbestos Litigation Docket (known as "MARDOC"). See Gulf Oil Co., 995 F.2d at  639. Miller's five actions were transferred to MARDOC. As part of the MARDOC litigation, Miller produced an "Initial  Data Form" ("IDF"), a summary of basic information about each claim, for each of his five claims. Miller apparently  produced the IDFs within weeks or months of filing his complaints and made them available to Shippers as part of the  discovery process; however, the IDFs were not filed with the court. On the Rezendes IDF, Miller stated that Rezendes  suffered from colon cancer, but did not mention leukemia; under the heading labeled "Toxin," Miller inserted  "Asbestos-Tobacco Smoke." On Birch's IDF, Miller identified leukemia, in addition to other illnesses, and again identified  asbestos and tobacco smoke under the "Toxin" heading. Bowman's IDF did not specify any illness, but listed asbestos and  tobacco smoke as toxins. Hudson's IDF identified leukemia as an illness but listed only asbestos as a toxin. Pompey's IDF  identified leukemia as an illness and listed asbestos and tobacco smoke as toxins. At some point during the course of  litigation -- the timing is not clear from the record before us -- Miller also produced death certificates for each of the  deceased seamen which indicated that some form of leukemia was the cause, or a contributing factor to, each sailor's death.


9
In 1991 and 1992, the Judicial Panel on Multidistrict Litigation transferred thousands of asbestos claims, including the  five cases Miller currently appeals, to the Eastern District of Pennsylvania for pretrial proceedings, pursuant to 28 U.S.C.  §1407. See In re Asbestos Prods. Liab. Litig., 771 F. Supp. 415 (J.P.M.L. 1991). In July 1993, Miller filed a "Motion to  Strip and Remand" in each of the five cases on appeal. In the motions, Miller asked the court to strip his claims of all  allegations relating to asbestos exposure "so as not to prejudice allegations unrelated to asbestos exposure appertaining [to]  toxin exposure which resulted in affliction of the respective seamen, whether living or deceased, of leukemic disease."2  Judge Weiner granted the motion in November 1993, and issued an order transferring the seamen's cases back to the  Northern District of Ohio for further resolution. In so doing, Judge Weiner found that the "form of action in thesecases is  now dissimilar to traditional asbestos-related, personal injury actions," and that plaintiff seamen had "abandoned any claim  for recovery based upon injury resulting from asbestos exposure and . . . are hereby precluded from claiming damages  resulting from injury due to exposure to asbestos products."


10
In March 1995, Shippers filed a consolidated motion for a more definite statement of Miller's claims, see Fed. R. Civ. P.  12(e), arguing that because Miller had not specifically pleaded either leukemia or benzene exposure, his complaints were  insufficient to put them on notice of the benzene claims he now argued. The court granted the motion in January 1996,  finding the complaints to be vague and ambiguous. The court ordered Miller to file amended complaints within sixty days  addressing several issues, including Miller's theory of liability and "the specific cargo or other substances aboard each  vessel alleged to have contained benzene." Although the district court dismissed the actions when Miller failed to file the  amended complaints within the sixty-day time period, the court reinstated the claims in February 1997, pursuant to Fed. R.  Civ. P. 60(b).


11
In April 1997, Miller filed amended complaints on behalf of the estates of each of the deceased seamen. In the amended  complaints, Miller again alleged theories of liability under both the Jones Act, 46 U.S.C. § App. 688, and general admiralty  and maritime law. Miller claimed that his decedents had suffered from leukemia as a result of exposure to benzene and  benzene-containing products, and listed specific instances and methods of exposure on particular ships. In April 1998,  Shippers filed for summary judgment, arguing that Miller's 1997 amended complaints did not relate back to his original  complaints, which had been filed in 1990-1992. Shippers also argued in each case that Miller's survival action was barred  by the three-year statute of limitations because his claims had accrued before decedent's deaths, and thus more than three  years prior to the filing of the original claims3.


12
The district court granted summary judgment to Shippers in each case. In five nearly identical memorandum opinions,  the court addressed only the relation-back question, finding that none of the amended complaints related back to the  original filing. The court relied on Shippers' uncontested argument that different toxins and different methods of exposure  cause different diseases, and found that "[e]xposure to benzene does not occur or act in the same manner as exposure to  asbestos." The court found that Miller's original allegation that seamen had been exposed to "hazardous substances other  than asbestos" was insufficient to put Shippers on notice of the benzene-related claims, and concluded that "[t]aken to its  logical conclusion, Plaintiff's position means the Defendants are forever on notice of claims arising out of exposure to any  hazardous substance." Miller filed a timely notice of appeal.

II. STANDARD OF REVIEW

13
The parties disagree about the standard by which we review the district court's decision that Miller's amended  complaints do not relate back to his original complaints for purposes of Rule 15(c)(2). Miller argues that this court reviews de novo a grant of summary judgment based on the running of a statute of limitations. Shippers argue that we review the  district court's decision for abuse of discretion.


14
The standard of review for the district court's summary judgment order is, of course, de novo. See Smith v. Ameritech,  129 F.3d 857, 863 (6th Cir. 1997). Further, Miller is correct that this court reviews de novo a district court's determinationthat a complaint was filed outside the relevant statute of limitations. See Tolbert v. State of Ohio Dep't of Transp., 172 F.3d  934, 938 (6th Cir. 1999). The district court's order turns, however, on the court's finding that Miller's amended claims do  not relate back to the original claims pursuant to Rule 15(c)(2). As we shall discuss, the question of whether an amended  claim relates back to an earlier filed complaint pursuant to Fed. R. Civ. P. 15(c)(2) requires us to determine whether the  amended claim "arose out of the conduct, transaction, or occurrence set forth or attempted to be set forth in the original  pleading." See Fed. R. Civ. P. 15(c)(2). This inquiry requires us to apply the legal standard of Rule 15(c)(2) to a given set of  facts, a task we are no less suited to perform than the district court. See Slade v. United States Postal Service, 875 F. 2d  814, 815 (10th Cir. 1989) (stating that application of Rule 15(c) to undisputed facts is "purely legal determination" that is  reviewed de novo); Paul Revere Life Ins. Co. v. Brock, 28 F.3d 551, 553 (6th Cir. 1994) (stating that mixed questions of  law and fact are reviewed de novo). Accordingly, we review de novo the district court's decision to deny relation back of an  amended complaint to the original complaint. See Dominguez v. Miller (In re Dominguez), 51 F.3d 1502, 1509 (9th Cir.  1995) (stating that review of Rule 15(c)(2) decision that permits or denies amendment to add a new claim against defendant  named in original complaint is de novo).

III. DISCUSSION

15
On appeal, Miller argues that the district court erred by finding that the amended complaints do not relate back to the  original complaints.4 Miller's argument is comprised of essentially three assertions: 1) that the Federal Rules of Civil  Procedure require a plaintiff to give a defendant only general notice of his claims, and that Millers's original complaints  provided such notice; 2) that his amended complaints relates back because the claims in the amended complaints arose out  of the same conduct, transaction, or occurrence as set forth in his original complaints; and 3) that both the original  complaints and information outside of the complaints gave Shippers adequate notice of their potential liability for the  claims raised in the amended complaints.

A. General Notice Required by Rules

16
Miller first argues that the Federal Rules of Civil Procedure require only that a pleading contain a short and plain  description of the court's jurisdiction, the pleader's claim for relief, and a demand for the judgment the pleader seeks. See Fed. R. Civ. P. 8(a). Miller contends that his original complaints, which alleged that the deceased seamen's injuries were  caused by exposure to "asbestos and hazardous substances other than asbestos," were sufficient to cover his subsequent  allegations of benzene-related claims. There can be no dispute that our modern rules of civil procedure are based on the  concept of "simplified 'notice pleading,'" Conley v. Gibson, 355 U.S. 41, 47 (1957), and that "[a]ll pleadings shall be so  construed as to do substantial justice."Fed. R. Civ. P. 8(f). This can indeed be seen in the basic requirements for a claim for  relief as set forth in Rule 8(a),5 and in the dictate of Rule 15(a), which states that a court shall grant a party leave to  amend a complaint "freely . . . when justice so requires." Fed. R. Civ. P. 15(a); see also Moore v. City of Paducah, 790 F.2d  557, 559 (6th Cir. 1986). This fundamental tenor of the Rules is one of liberality rather than technicality, and it creates an  important context within which we decide cases under the modern Federal Rules of Civil Procedure. Nonetheless, this  tenor does not necessarily mandate a particular outcome on its own, as Miller suggests. Rather, we must examine the more  specific requirements of Rule 15(c) in order to determine whether Miller's amended complaints relate back to the original  pleadings.

B. Same Conduct, Transaction, or Occurrence

17
Rule 15(c)(2) states that:  An amendment of a pleading relates back to the date of the original pleading when... the claim or defense asserted  in the amended pleading arose out of the conduct, transaction, or occurrence set forth or attempted to be set forth in  the original pleading.


18
Fed. R. Civ. P. 15(c)(2). As this court recently explained, whether a statute of limitations will be permitted to bar an  amended claim turns on whether the amended claim arose out of the same conduct, transaction, or occurrence as that set  forth in the original complaint:


19
The rule is based on the notion that once litigation involving particular conduct or a given transaction or occurrence  has been instituted, the parties are not entitled to the protection of the statute of limitations against the later assertion  by amendment of defenses or claims that arise out of the same conduct, transaction, or occurrence as set forth in the  original pleading.


20
Brown v. Shaner, 172 F.3d 927, 932 (6th Cir. 1999).


21
This court has stated that "the thrust of Rule 15 is to reinforce the principle that cases 'should be tried on their merits  rather than the technicalities of pleadings.'" Moore, 790 F.2d at 559 (quoting Tefft v. Seward, 689 F.2d 637, 639 (6th Cir.  1982)). Thus, a court will permit a party to add even a new legal theory in an amended pleading as long as it arises out of  the same transaction or occurrence. See Hageman v. Signal L.P. Gas, Inc., 486 F.2d 479, 484 (6th Cir. 1973) ("where the  parties are the same, . . . an amendment which adds another claim arising out of the same transaction or occurrence does  relate back to the date of the original complaint."); Koon v. Lakeshore Contractors, 128 F.R.D. 650, 653 (W.D. Mich.  1988) ("an added theory of liability for the same occurrence may relate back." (citing Hageman)), aff'd without opinion,  889 F.2d 1087 (Table), 1989 WL 137151 (6th Cir. Nov. 15, 1989); see also 6A Wright et al., federal practice and procedure  § 1497, at 94-95, 98-99 (1990 & Supp. 2000) ("an amendment that states an entirely new claim for relief will relate back as  long as it satisfies the test embodied in . . . Rule 15(c)."). Likewise, "[a]n amendment that alleges added events leading up  to the same injury may relate back." Koon, 128 F.R.D. at 653 (citing Tiller v. AtlanticCoast Line R. Co., 323 U.S. 574, 581  (1945)).


22
Miller argues that the amended claims arose out of the same conduct, transaction, or occurrence as the original claims. See Fed. R. Civ. P. 15(c)(2). Miller asserts that, under the amended complaints, Shippers are liable for the same conduct --  negligently exposing the deceased seamen to toxins and failing to maintain the seaworthiness of their vessels -- as he  alleged in his original complaints. He further claims that the amended complaints simply named the "hazardous substance  other than asbestos" with more specificity than did the original complaints, and that the two sets of complaints concerned  the same time period and the same injuries.


23
Under the Rules described above, we find this argument to be persuasive. Miller brought his original complaints under  the Jones Act, 46 U.S.C. § App. 688, and general admiralty and maritime law. The original complaints included theories of  negligence, unseaworthiness, wrongful death, and loss of society and companionship. The amended complaints also arise  under the Jones Act and general admiralty and maritime law, and include theories of negligence, unseaworthiness, wrongful  death, and loss of society and companionship. More important, each original complaint alleged that, "[w]hile serving as a  mariner on said vessels, Plaintiff's decedent was exposed to hazardous substances other than asbestos," and that "[a]s a  direct and proximate consequence of his exposure to hazardous substances other than asbestos, Plaintiff's decedent has  sustained injuries." The amended complaints are very similar, with the added specificity that the "hazardous substances"  originally pleaded included benzene and that the injuries originally claimed came in the form of leukemia. Each amended  complaint states that "Plaintiff's Decedent was required by his employers to perform duties which included the constant  exposure to chemical carcinogens including benzene," and that that exposure caused the decedent to suffer from leukemia.  The amended complaints then state the particular benzene-containing substances to which each decedent was allegedly  exposed, and on which ship the exposure occurred. Thus, the amended complaints simply plead with more specificity that  which appeared in the original complaints: Shippers' liability for exposing decedents to a hazardous substance. See Tiller,  323 U.S. at 581 ("The cause of action now, as it was in the beginning, is the same -- it is a suit to recover damages for the  alleged wrongful death of the deceased."); see also 3 James Wm. Moore et al., moore's federal practice §15.19[2], at 15-82  (3d ed. 1999) ("Amendments that amplify or restate the original pleading or set forth facts with greater specificity should  relate back.").


24
Shippers argue strenuously that the amended complaints do not arise out of the same conduct, transaction, or occurrence  as the original complaints, because they contain new "operative facts."6 It is true that a claim with entirely different  "operative facts" will not relate back. See Koon, 128 F.R.D. at 653 (finding that new claim of lower back injury sustained  while jumping to the ground from a fence does not relate back to original complaint of neck injury sustained while lifting  heavy object on board a barge). But Miller alleged the very same general set of facts in the amended complaints as he did in the original ones: that decedents worked for many years on Shippers' vessels, that they were exposed to hazardous substances duringthat time due to Shippers' negligence, and that they sustained injuries in the form of lethal diseases due to  their exposure to hazardous substances. Shippers' arguments that injuries arising from exposure to asbestos are materially  different from injuries arising from exposure to benzene -- an argument which is derived from a few definitions in a  medical dictionary, see Dorland's Illustrated medical dictionary 145-46, 191 (28th ed. 1994), and upon which the district  court relied -- is unconvincing. To focus on the particular pathologies of a given carcinogen is far too formalistic and  specific for the general, non-technical requirements of Rule 15. This is especially the case with diseases such as cancer and  leukemia, which may be idiopathic and which may arise from sources that are impossible to identify before extensive  discovery (if at all). Accordingly, the benzene exposure claims Miller details in the amended complaints fit comfortably  within the claims of exposure to "hazardous substances" that he alleged in the original pleading7.

C. Notice to Shippers

25
Although the focus of our inquiry into whether an amendment relates back pursuant to Rule 15(c)(2) is whether it arises  from the same conduct, transaction, or occurrence, we look to other factors as well. "Undue delay in filing, lack of notice to  the opposing party, bad faith by the moving party, repeated failure to cure deficiencies by previous amendments, undue  prejudice to the opposing party, and futility of amendment are all factors which may affect the decision." Hageman, 486  F.2d at 484. Of these factors, "[n]otice and substantial prejudice to the opposing party are critical . . . in determining  whether an amendment should be granted." Id.; see also Brown, 172 F.3d at 934 (permitting relation back of amended  complaint where defendants "'knew or should have known'" that they were targets of § 1983 suit).


26
Miller argues that his original complaints put Shippers on notice that they must defend Jones Act and general maritime  law toxic tort actions which alleged wrongful death due to exposure to asbestos and/or other hazardous substances.  Shippers respond that Miller's non-specific, general allegations were insufficient to put them on notice of his  benzene-related leukemia claims8.  In this context, the partiesargue the relevance of Tiller v. Atlantic Coast Line R. Co.,  323 U.S. 574 (1945), to the instant case. In Tiller, the wife of a railroad employee who was killed on the job sued the  defendant rail company under the FELA, 45 U.S.C. § 51 et seq. See 323 U.S. at 575. The plaintiff alleged that her  husband's death was caused by the negligent operation of a railroad car that struck and killed him and by  defendant-railroad's failure to provide her husband with a reasonably safe place to work. Id. Plaintiff later filed an amended  complaint in which she added a claim under the Federal Boiler Inspection Act, charging that the locomotive was not  properly lighted. See id. at 580-81. Applying Rule 15(c), the Court held that both complaints "related to the same general  conduct, transaction, and occurrence," and that defendant "had notice from the beginning that [plaintiff] was trying to  enforce a claim against it because of the events leading up to the death of the deceased in the [defendant's] yard." Id. at 581.


27
Shippers contend that Tiller is inapposite to the instant case because the amendment in Tiller did not fundamentally  change the nature of plaintiff's claim, in that both the original claim and the amended claim involved a single, traumatic  incident within the defendant's knowledge. Shippers assert that they, in contrast to the Tiller defendant, had no knowledge  of the deceased seamen's leukemic injuries until Miller filed the amended complaints, many years after decedents were  allegedly injured. We disagree. The original complaints in this case made clear that the deceased seamen had suffered latent  injuries, based upon exposure to toxic substances on board Shippers' vessels, that resulted in their illnesses and eventual  deaths. See Benco Plastics, Inc. v. Westinghouse Elec. Corp., 387 F. Supp. 772, 783 (E.D. Tenn. 1974) (stating that "the  rule to be followed in federal courts is that if there is an identity between the amendment and the original complaint with  regard to the general wrong suffered and with regard to the general conduct causing such wrong, then the amendment shall  relate back and the statute of limitations would not avail to preclude a hearing on the merits." (internal quotation marks and  citation omitted)). The amended claim in Tiller appears to have gone further yet, stating a new theory of recovery by  referring to a statute not alleged in the original complaint (i.e., the Federal Boiler Inspection Act).  See id. at 580. Yet, the Tiller Court found that the defendants were on notice based upon the original complaint. Id. at 581. We thus conclude that  the Tiller Court's broad application of Rule 15(c) supports Miller's relation-back theory. See id. at 580-81.


28
Nor are we persuaded by Shippers' argument that Miller's original complaints were so general that, if they are construed  to give notice of benzene-related leukemia claims, defendants in asbestos cases will be forever on notice of claims arising  out of exposure to any hazardous substance. The district court relied on this reasoning in its decision, finding that "the  Court would emasculate the statute of limitations requirement if it gave to the phrase 'hazardous substances other than  asbestos' the breadth [Miller] seeks." This reasoning is only facially appealing. The complaints in this case alleged that Shippers' former employees had died as a result of being exposed to hazardous substances aboard the vessels Shippers  owned and operated. Shippers were on notice that they needed to collect and preserve evidence relating to the working environment in their ships. Miller, for his part, had the right and responsibility to pursue through discovery the nature and circumstances of decedents'working environments and deaths. To be sure, both parties may have had difficult tasks in  conducting this discovery, but that difficulty goes to the substance of the lawsuit rather than to whether Shippers knew that  they were being sued, and on what general grounds. If, at some point in the future, Miller attempts to amend his claim  again, the court will be free to determine whether it should relate back, looking to possible prejudice to the parties,  unwarranted delay, futility, and the other factors appropriately considered under Rule 15(c). See Hageman, 486 F.2d at 484.  These factors are an adequate protection against Shippers being forever liable for claims arising from Miller's original  pleading.


29
One more case demands our discussion. The parties argue the relevance of Smith v. Gulf Oil Co., 995 F.2d 638 (6th Cir.  1993), in which this court held that the district court did not abuse its discretion under Fed. R. Civ. P. 16 by foreclosing  plaintiff-seamen's argument that injuries they alleged were caused by tobacco smoke in defendants' ships. Id. at 644. In Smith, seamen brought asbestos claims similar to the original claims in the instant case. Id. at 640. As in the instant case,  the Smith plaintiffs alleged that their injuries resulted from exposure to asbestos and to "hazardous substances other than  asbestos." Id. at 643. The plaintiffs pursued only the asbestos claims until two days after trial commenced. See id. at 642.  When the Smith defendant-shipowners moved to argue evidence of plaintiff seamen's individual smoking habits in  defending, plaintiffs moved to argue that tobacco smoke was a hazardous condition for which the shipowners could be  liable. Id. at 640. This court upheld the district court's ruling that plaintiff seamen could not argue the tobacco theory on the  grounds that plaintiff's counsel had never seriously pursued it. Id. at 644.


30
The relevance of Smith to this case is minimal. First, we typically review a district court's case-management decision  made pursuant to Rule 16 for abuse of discretion. See, e.g., Muckleshoot Tribe v. Lummi Indian Tribe, 141 F.3d 1355, 1358  (9th Cir. 1998). As discussed supra, we review the district court's decision to forbid relation back pursuant to Rule 15(c)(2) de novo. See Dominguez, 51 F.3d at 1509. Second, counsel in Smith never formally pursued the tobacco theory, but rather  adopted it as a trial tactic at the last minute. Id. at 643. In the instant case, Miller filed amended complaints alleging the  benzene claims, and pursued them in the lower court. Thus, Smith has little relevance to the instant case.

IV. CONCLUSION

31
For the reasons discussed, we REVERSE the decision of the district court and REMAND the case for further  proceedings consistent with this opinion.



Notes:


1
  Title 46 U.S.C. § App. 688(a) provides:  Any seaman who shall suffer personal injury in the course of his employment may, at his election, maintain an action  for damages at law, with the right of trial by jury, and in such action all statutes of the United States modifying or  extending the common-law right or remedy in cases of personal injury to railway employees shall apply; and in the  case of the death of any seaman as a result of any such personal injury the personal representative of such seaman  may maintain an action for damages at law with the right of trial by jury, and in such action all statutes of the United  States conferring or regulating the right of action for death in the case of railway employees shall be applicable.
The statute's incorporation of statutes applying to railway employees refers to the Federal Employers' Liability Act (FELA),  45 U.S.C. §§ 51 et seq. See Hernandez v. Trawler Miss Vertie Mae, Inc., 187 F.3d 432, 436 (4th Cir. 1999).


2
  In an affidavit dated September 27, 1993, Miller's counsel stated that the only causes of action the deceased seamen  wished to pursue were those related to their deaths by leukemia, which he alleged were caused by exposure to benzene.


3
  In addition, Shippers alleged in their motions for summary judgment that Rezendes could not prove that he died of  leukemia, and that Hudson's wrongful death claim was barred by the applicable statute of limitations. The district court did  not reach these arguments. See infra, note 4.


4
  Miller argues in the alternative that the district court erred by failing to determine whether the causes of action in the  amended complaints did not accrue until he was aware of both the nature of the decedent seamen's injuries and their cause.  Because we find that Miller's amended complaints do relate back to the original complaints, we do not reach this alternative  argument. Nor do we pass judgment on Shippers' argument that even Miller's original claims were filed outside of the  relevant statute of limitations, as we are not inclined to review a theory which, as in this case, the district court has not first  reviewed. See United States v. Baker, 807 F.2d 1315, 1321 (6th Cir. 1986) (stating that "courts of appeals generally refuse  to consider issues not passed upon by lower courts"). We reach only the question of whether Miller's amended claims relate  back to the original claims pursuant to Rule 15(c)(2), and leave it to the district court to resolve on remand whatever further  issues may exist in this case.


5
  Fed. R. Civ. P. 8(a) states:  (a) Claims for Relief. A pleading which sets forth a claim for relief, whether an original claim, counterclaim,  cross-claim, or third-party claim, shall contain (1) a short and plain statement of the grounds upon which the court's  jurisdiction depends, unless the court already has jurisdiction and the claim needs no new grounds of jurisdiction to  support it, (2) a short and plain statement of the claim showing that the pleader is entitled to relief, and (3) a demand  for judgment for the relief the pleader seeks. Relief in the alternative or of several different types may be demanded.


6
  Shippers also propose that the court evaluate whether the complaints arise out of the same conduct, transaction, or  occurrence by using two tests: 1) whether the evidence offered in support of the original claim would prove the new claim,  and 2) whether the new claim alters the "when, where, what, or how" of the alleged injury. We reject these formulations as  being too mechanical for the liberal approach of Rule 15(c). See6A Wright et al. § 1498, at 102-03 (noting that mechanical  tests are "too narrow and restrictive, out of harmony with the Federal Rules, and ought to be replaced with an approach that  takes an over-all view of the problem." (internal quotation marks and citation omitted)).


7
  The dissent argues that the amended complaints substantially altered the factual basis of Miller's original claims in that  "the mechanisms, times, circumstances of, and diseases caused by shipboard exposure to benzene differed significantly  from those of shipboard exposure to asbestos." Miller's original complaint, however, did not contain any asbestos-specific  allegations of such "mechanisms, times, circumstances . . ., and diseases." Rather, Miller's original allegations relating to  the circumstances in which the decedents sustained their injuries were essentially bare statements that the decedents had  been exposed to asbestos and other hazardous substances onboard Shippers' vessels. While it is true that Miller's amended  complaint more specifically described the substances aboard each vessel alleged to have contained benzene, these claims do  not substantially alter the factual basis of Miller's original charges. On the contrary, Miller's amended complaint simply  reflects a more particularized statement of his original claim of exposure to "hazardous substances other than asbestos."


8
  Miller also claims that certain evidence extrinsic to the pleadings gave Shippers notice of his benzene-related leukemia  claims. Shippers disagree, arguing that notice of an additional claim must be found within the original complaint itself  rather than in extrinsic sources. The dissent appears to agree with Miller that extrinsic evidence is relevant to the notice  question, but points out that the IDFs submitted by Miller to Shippers during discovery failed to mention benzene as a  possible toxin. Although we are inclined to believe that notice may be provided by sources outside the pleadings, see6A  Wright et al. § 1497, at 92-93 (stating that permitting extrinsic evidence to serve as notice "seems sound since it is unwise  to place undue emphasis on the particular way in which notice is received."); 27A Lawyer's Cooperative Publishing, federal  procedure: lawyers edition § 62:336, at 127 (1996) ("notice may ... be received from outside the pleadings"), we do not  decide the instant case based upon either Miller's or the dissent's extrinsic evidence. Rather, we find that Miller's original  complaints provided Shippers with adequate notice of the charges raised in the amended complaints.



32
RALPH B. GUY, JR., Circuit Judge, dissenting.


33
Even under the de novo standard of review, I cannot agree that the  amended complaints at issue in this case relate back to the date of the original pleadings under Rule 15(c)(2). The rationale  behind this rule is to allow relation back when the defendant has been put on notice, through the pleadings or other sources,  of the entire scope of the transaction or occurrence. See Barcume v. City of Flint, 819 F. Supp. 631, 636 (E.D. Mich. 1993)  (citing Wright, Miller & Kane, Federal Practice and Procedure Civil 2d §§ 1496-97). The focus of the inquiry is not  whether the claim or theory in the amended complaint is new, but rather whether it arose out of the same conduct,  transaction, or occurrence. See Hageman v. Signal L.P. Gas, Inc., 486 F.2d 479, 484 (6th Cir. 1973) (added theory for same  occurrence may relate back)1.  An amendment that states a claim basedupon different facts will not relate back to the date  of the original complaint. See Koon v. Lakeshore Contractors, 128 F.R.D. 650, 653 (W.D. Mich. 1988), aff'd without  opinion, 889 F.2d 1087 (6th Cir. 1989) (amendment alleging negligence and unsafe working conditions under Jones Act  did not relate back because it involved different injuries that occurred in different ways).


34
In this case, the original complaints alleged injuries from exposure to "asbestos" and "hazardous substances other than  asbestos." The complaints did not mention leukemia, benzene, or any toxin other than asbestos. Each of the IDF's provided  to the defendants shortly after the cases were filed identified the toxin either as "asbestos and tobacco smoke" or "asbestos,"  but did not mention benzene. The majority's conclusion that the amended complaints merely pled with more specificity the  same claims, ignores the district court's finding that the original complaints did not give adequate notice of the benzene  claims. I agree with the district court that the amended complaints substantially altered the factual basis for the toxic tort  claims by alleging that the decedents suffered from leukemia caused by exposure to dangerous concentrations of benzene in  the air, potable water, and on exposed skin from working with or in close proximity to products containing benzene. There  is no dispute that the mechanisms, times, circumstances of, and diseases caused by shipboard exposure to benzene differed  significantly from those of shipboard exposure to asbestos. These are the operative facts that determine whether the  amendments arose from the same conduct, transaction, or occurrence as the original complaints. For these reasons, I  respectfully dissent.



Note:


1
  For example, in Tiller v. Atlantic Coast Line R. Co., 323 U.S. 574 (1945), the amendment added a new claim arising  out of a single accident that led to the death of a railroad employee. In Brown v. Shaner, 172 F.3d 927, 932-33 (6th Cir.), cert. denied, 120 S. Ct. 403 (1999), the amended complaint alleged the same claims under 42 U.S.C. § 1983, but added the  allegations that the defendants were being sued in their individual capacities. Not surprisingly, the court in Brown found  that the amendment related back to the filing of the original complaint.


