227 F.3d 776 (7th Cir. 2000)
NutraSweet Company,  and Monsanto Company, Plaintiffs-Appellees,v.X-L Engineering Company,  and Paul T. Prikos, individually, Defendants-Appellants.
No. 99-3863
In the  United States Court of Appeals  For the Seventh Circuit
Argued April 11, 2000Decided September 8, 2000

Appeal from the United States District Court  for the Northern District of Illinois, Eastern Division.  No. 95 C 6024--Charles R. Norgle, Sr., Judge.[Copyrighted Material Omitted][Copyrighted Material Omitted][Copyrighted Material Omitted]
Before Manion, Diane P. Wood, and Evans, Circuit  Judges.
Manion, Circuit Judge.


1
The Comprehensive  Environmental Response, Compensation and  Liability Act of 1980 ("CERCLA"), 42 U.S.C. sec.  9601 et seq., allows private parties to recover  the costs they incur in cleaning up hazardous  wastes. NutraSweet and Monsanto (collectively  "NutraSweet") sued X-L Engineering and its  president and principal shareholder, Paul Prikos  (collectively "X-L"), for improperly disposing of  hazardous compounds which contaminated  NutraSweet's property. The district court entered  partial summary judgment in favor of NutraSweet,  finding X-L to be at least partly responsible for  the hazardous wastes on NutraSweet's property.  After a bench trial, the district court found  that X-L was in fact 100% liable for these wastes  and awarded NutraSweet the full amount of its  requested damages. X-L raises numerous issues  concerning the proceedings below. We affirm in  all respects.

I.  Background

2
NutraSweet (a subsidiary of Monsanto) owned a  food manufacturing facility in Niles, Illinois.  Its neighbor to the east was X-L Engineering, a  machine shop. In October 1990, NutraSweet thought  about expanding its Niles facility on vacant land  on the east side of its property (which bordered  the west side of X-L's shop), so it ordered soil  testing of that area. The tests revealed high  levels of hazardous volatile organic compounds  ("VOCs") near X-L's property. That month  NutraSweet hired another company to perform a  "phase one" assessment of the problem; the  assessment concluded that spills at X-L could  have caused the contamination.


3
In the spring of 1992, NutraSweet employees  began observing an X-L employee dumping out  wastewater from a mop-bucket on the west side of  X-L's property near NutraSweet's property.  NutraSweet sampled the wastewater and found that  it contained a VOC called "trichloroethene" (or  "TCE"). It also took a soil sample from X-L's  property where the mop-bucket dumping was  observed. This sample also contained TCE.  NutraSweet began video surveillance of X-L's  dumping, and after one month, it recorded 82  occasions where an X-L employee had dumped  wastewater onto X-L property next to NutraSweet's  property, and four occasions in which the  standing wastewater had spilled onto NutraSweet's  property.


4
At NutraSweet's request, the Illinois EPA and  State Police also began surveillance of X-L. On  two occasions, state officials observed X-L  dumping wastewater on its own property but near  NutraSweet's property. On the second occasion  they sampled the wastewater; it contained TCE,  another VOC called perchloroetylene (or "PCE"),  and several other hazardous compounds, including  trichloroethane (or "TCA"). The dumping ended in  July 1992, when the officials returned to X-L for  a third inspection, wherein they confronted  Prikos, X-L's owner. At the beginning of this  inspection, the officials repeatedly observed the  same X-L employee again dumping wastewater onto  X-L property that was adjacent to NutraSweet's  property. The inspectors sampled the wastewater  just before it was dumped; TCA was again present.


5
NutraSweet hired an environmental consulting  firm, Geraghty and Miller ("G & M"), to  investigate and plan for the "remediation" (or  clean-up) of its property. G & M tested the soil  and designed and implemented a plan with Illinois  EPA approval and under its supervision.  NutraSweet cleaned up the property until the  agency told it that the remediation had succeeded  to the maximum extent possible. NutraSweet then  sued X-L under CERCLA and the Declaratory  Judgment Act, 28 U.S.C. sec.sec. 2201-2202 (with  common law claims for nuisance, trespass and  negligence). See NutraSweet Co. v. X-L Eng'g  Corp., 933 F. Supp. 1409, 1412 (N.D. Ill. 1996).

II.  The Proceedings Below

6
NutraSweet moved for summary judgment as to both  liability and damages. It produced considerable  evidence to establish that X-L was responsible  for at least some of the contaminates on its  property, such as:


7
1. the videotape of X-L's mop-bucket dumping;


8
2. eyewitness accounts of this dumping (from  NutraSweet employees, Illinois EPA officials, and  Illinois State Troopers);


9
3. NutraSweet's 1992 soil and water samples which  revealed the same VOCs in the mop-bucket  wastewater as were present in the area of  NutraSweet's property onto which the wastewater  had spilled, and as were present in an  immediately adjacent area of X-L's property where  the dumping was observed;


10
4. test results from Illinois officials of the  contents of the wastewater which showed the same  VOCs as were found on NutraSweet's property;


11
5. an affidavit from G & M stating that the  highest level of VOCs on NutraSweet's property  were near X-L's property where the dumping was  observed and that the groundwater flowed away  from X-L's property to NutraSweet's property;


12
6. records from X-L showing its use of a TCA-based  solvent; and


13
7. an affidavit stating that NutraSweet did not  use chlorinated solvents in its manufacturing  process, and it never used such solvents at its  facility except for a self-contained parts  cleaner that was returned to the manufacturer for  recycling and which never had any releases during  the two years that NutraSweet used it.


14
In response, X-L admitted that it used chemical  solvents in its business, and it did not  establish that prior to 1992 it had properly  disposed of spent solvents (X-L stated that "in  the 1992 time frame" it disposed of spent  solvents through licensed waste haulers). Also,  Prikos stated that to "the best of his knowledge"  no X-L employee "has ever dumped or otherwise  discarded any item on the NutraSweet property."  But as to the X-L employee caught on video "mop-  bucket dumping," Prikos stated that he was  unaware "of the specifics as to how [that  employee] went about his duties and how he  disposed of the mop water." Prikos added that  after Illinois officials told him about the mop-  bucket dumping, he "issued orders directed to  ensure that [the employee] would no longer dump  mop water on or about [the area in question],"  and that although Prikos had "no personal  knowledge that [the employee] ever did dump mop  water in or near [the area in question], it is my  understanding that, after I indicated that this  [dumping] should not be done, that it was never  done again." X-L's only other affidavit was from  its expert, Richard Shepherd, an environmental  engineer, who opined that NutraSweet had failed  "to prove, through a degree of scientific  certainty, that X-L Engineering Company was the  cause of contamination found on the NutraSweet  Property, much less the sole cause." Shepherd's  conclusion was based on the lack of a "chemical  fingerprint" which, in turn, was based on his  assumption that TCA was the only VOC that X-L  ever used. Shepherd also concluded that the  groundwater flowed away from NutraSweet's plant,  thus showing (he believed) that any solvents  dumped on X-L property could not have "migrated"  onto NutraSweet's property.


15
In reply, NutraSweet's experts used Illinois EPA  reports to show that all twelve of the VOCs on  NutraSweet's property were found on X-L's  property where the dumping had occurred, thus  showing, NutraSweet contended, a "chemical  fingerprint." A NutraSweet expert also disputed  Shepherd's analysis of groundwater migration. He  opined that Shepherd's conclusion was faulty  because it reflected rainwater recharging of the  soil--a condition where rainwater briefly alters  the "normal" direction of flow. NutraSweet's  experts stated that they measured the groundwater  flow in the winter when the ground was frozen,  thus minimizing the effect of rainwater  recharging and indicating the usual direction of  groundwater migration, which was away from X-L's  property to NutraSweet's property. Finally, a  NutraSweet expert stated that based upon his  review of the surveillance tapes, X-L's dumping  along a railroad ditch to the north of its  property sometimes created a 50-foot wide pond of  wastewater that would extend onto NutraSweet's  property. Soil samples from this area of  NutraSweet's property revealed the presence of  VOCs.


16
The district court found that there was no  genuine dispute that X-L was responsible under  CERCLA for at least some of the VOCs on  NutraSweet's property and that it was liable to  NutraSweet under state law for nuisance, trespass  and negligence. NutraSweet, 933 F. Supp. at 1422-  25. Because X-L did not respond at all to  NutraSweet's evidence of its clean-up costs  (about $560,000), the district court found that  its costs were those NutraSweet put forth. Id. at  1415. The court entered partial summary judgment  for NutraSweet on X-L being at least partially  liable for NutraSweet's costs. It ordered a trial  on the remaining issue: the amount of VOCs for  which X-L was responsible (which would determine  its liability). Id. at 1423-25.


17
In preparing for trial, X-L repeatedly missed  deadlines. It first failed to make Shepherd  available for a deposition or to produce its  expert witness report on time. As a result,  NutraSweet moved under Fed. R. Civ. P. 37(c) to  bar Shepherd from testifying at trial. The  district court struck the trial date and ordered  the parties to brief whether Shepard should be  barred. X-L then filed Shepherd's report, one  week after the deadline. This late filing  prejudiced NutraSweet's ability to examine  Shepherd on his theory as to why X-L was not  liable for the VOCs. NutraSweet therefore  requested that the court bar Shepherd from  testifying or in the alternative, that it be  allowed to take soil samples from X-L's property  to rebut the factual assumptions and theories in  Shepherd's report. The district court again  declined to bar Shepherd from testifying, but  agreed to allow each side to take soil samples  from the NutraSweet and X-L sites, which the  parties completed in October 1997.


18
The district court set a new trial date for July  14, 1998 and directed the parties to disclose  their reports of the site work by March 4, 1998.  NutraSweet complied with the March 4 deadline,  but X-L did not. One week after the deadline, X-L  sought another extension for filing its report of  the site work, an extension for filing its  supplemental expert witness report on the site  work, and an extension for other pretrial  deadlines. To support its motion, X-L noted that  because of the extensive field work that was  done, NutraSweet would probably be supplementing  its theories of the case, and for that reason X-L  would need additional time to respond to  NutraSweet's supplemental expert report. The  district court granted X-L's motion and set pre-  trial deadlines as X-L had proposed.


19
NutraSweet filed the supplemental expert report  of its rebuttal expert, Dr. Roy Ball, a week  early on March 20, 1997. X-L's supplemental  report was due on April 10, 1997, but it did not  meet this deadline. A week later, X-L moved for  an extension of time until May 5, 1998. The  district court did not act on this motion, but it  was just as well that it didn't because that  proposed deadline also came and went, with X-L  still not filing a supplemental report.  NutraSweet again moved to bar expert testimony  that went beyond Shepherd's initial expert  report. Finally, about six weeks after the April  10, deadline, X-L responded by complaining that  Ball's report was not sufficiently specific and  that it expanded NutraSweet's theory of the case.  X-L argued that it should not be required to file  a supplemental report until NutraSweet filed a  more complete report. The district court granted  NutraSweet's motion, limiting Shepherd's trial  testimony to his initial report and precluding  him from testifying on the results of the site  work.


20
At trial, NutraSweet called Prikos to establish  that X-L had used cleaning solvents containing  TCA and PCE from 1973 (when Prikos acquired the  company) until the fall of 1992. He also  testified that X-L used PCE in its "hot  degreaser," it used a TCA-based solvent in its  "cold degreaser" beginning in the mid- to late  1970s, and X-L cleaned parts a third way by  dropping them into a bucket (he did not know  whether PCE was used in cleaning parts this way).  G & M's supervising hydrologist testified that  the soil and groundwater samples from X-L's  property showed concentrated solvent dumping. Dr.  Ball, NutraSweet's expert, testified that  laboratory chromatograms of the PCE found on both  NutraSweet and X-L's property indicated that the  PCE was from essentially the same source but was  disposed of at different times. Various  methodologies that Ball used--such as the degree  of degradation or "speciation" of the VOCs at  each site, the rate of groundwater flow on the  NutraSweet site, and aerial photographs--  supported his theory that the dumping of solvents  began on X-L property when its shop was built in  the mid-1960's but moved over to NutraSweet's  property in the early 1980's (probably once X-L  had paved over part of its property, thereby  making dumping impracticable). Finally,  NutraSweet rebutted X-L's argument that it had  been properly disposing of its VOCs: it  introduced X-L's shipping manifests and Illinois  EPA records that showed that it was not until  December 1990 at the earliest (ten years after  federal regulations required proper disposal of  VOCs) that X-L began to dispose properly of VOCs.  In its case, X-L did not introduce any evidence  or proffer a theory as to who besides X-L could  have been responsible for the VOCs on  NutraSweet's property. The district court found  X-L 100% responsible and entered damages in favor  of NutraSweet equal to 100% of its costs (with  $113,000 in prejudgment interest, the total award  was thus $673,000).


21
X-L appeals the partial summary judgment in  favor of NutraSweet that X-L was at least partly  liable for the VOCs on NutraSweet's property. It  also appeals the district court's decision not to  allow it further time to file a supplemental  expert report and in limiting its expert's  testimony at trial. Furthermore, X-L contends  that the district court abused its discretion in  admitting the testimony of NutraSweet's expert,  and it contends that the court erred in denying  X-L's motion for a directed verdict. Finally, X-L  appeals the district court's finding at trial  that it was the source of all the VOCs on  NutraSweet's property and the determination of  damages.

III.  Discussion

22
Under sec. 107(a) of CERCLA, 42 U.S.C. sec.  9607(a), an owner of land is strictly liable for  hazardous wastes that are contaminating his  property. See Kerr-McGee Chem. Corp. v. Lefton  Iron & Metal Co., 14 F.3d 321, 325 (7th Cir.  1994) ("A responsible person includes the current  owner and any person who formerly owned and  operated the facility in question at a time of  actual or threatened release of a hazardous  substance."); id. at 326 (owners "are strictly  liable under CERCLA sec. 107"). But under sec.  113(f) of CERCLA, 42 U.S.C. sec. 9613(f), the  landowner "may seek contribution from another  person who is liable or potentially liable under  sec. 107." Kerr-McGee, 14 F.3d at 326. Thus,  under "the CERCLA statutory scheme, sec. 107 . .  . governs liability, while sec. 113(f) creates a  mechanism for apportioning that liability among  responsible parties." Town of Munster, Ind. v.  Sherwin-Williams Co., Inc., 27 F.3d 1268, 1270  (7th Cir. 1994).


23
In Azko Coatings, Inc. v. Aigner Corp., 30 F.3d  761, 764 (7th Cir. 1994), we noted that subpart  (B) of sec. 107(a) "permits any 'person'--not  just the federal or state governments--to seek  recovery of appropriate costs incurred in  cleaning up a hazardous waste site." As a result,  we indicated that a landowner who, although  technically strictly liable for hazardous wastes  on its property was innocent of the  contamination, would not have to bring a  contribution action under sec. 113(f) (because he  did not "contribute" to the contamination); he  could instead bring "a direct cost recovery  action" under sec. 107(a) against the responsible  party. Id. A few years later we held that an  innocent landowner could indeed use the "Azko  exception" to pursue a sec. 107 "direct cost  action." AM Int'l, Inc. v. DataCard Corp., DBS,  Inc., 106 F.3d 1342, 1347 (7th Cir. 1997); Rumpke  of Ind., Inc. v. Cummins Engine Co., Inc., 107  F.3d 1235, 1241 (7th Cir. 1997); see also PNC,  Inc. v. Sherwin-Williams Co., 151 F.3d 610, 617  (7th Cir. 1998) (noting availability of sec. 107  action for innocent landowners). Such an action  is available if "a landowner [is] forced to clean  up hazardous materials that a third party spilled  onto its property or that migrated there from  adjacent lands." Azko, 30 F.3d at 764; see also  Rumpke, 107 F.3d at 1240 ("the Azko exception"  certainly applies to "the landowner who discovers  someone surreptitiously dumping wastes on its  land"). To establish the Azko exception under  sec. 107(a), a plaintiff must establish that: (1)  the defendant is a covered person under sec.  107(a); (2) there is a release or threatened  release of a hazardous substance from a  "facility" as defined by sec. 101(9);1 (3) the  release caused the plaintiff to incur response  costs that are consistent with the national  contingency plan, Kerr-McGee, 14 F.3d at 325;  Dedham Water Co. v. Cumberland Farms Dairy, Inc.,  889 F.2d 1146, 1150 (1st Cir. 1989); and (4) the  plaintiff "did not pollute the site in any way."  Rumpke, 107 F.3d at 1241. In this case, the major  issue is whether the hazardous wastes on  NutraSweet's property were released from the X-L  facility.

A.  Summary Judgment

24
We review a grant of summary judgment de novo.  Miller v. American Fam. Mut. Ins. Co., 203 F.3d  997, 1003 (7th Cir. 2000). Summary judgment is  appropriate if "there is no genuine issue as to  any material fact and . . . the moving party is  entitled to judgment as a matter of law." Fed. R.  Civ. P. 56(c). To ward off summary judgment by  showing that there is a genuine dispute on a  material fact, the non-moving party must do more  than raise a "metaphysical doubt" as to the  fact's existence. Gleason v. Mesirow Fin., Inc.,  118 F.3d 1134, 1139 (7th Cir. 1997). The evidence  must be "such that a reasonable jury could return  a verdict for the nonmoving party." Anderson v.  Liberty Lobby, Inc., 477 U.S. 242, 248 (1986).  "If the evidence is merely colorable, or is not  significantly probative, summary judgment may be  granted." Id. at 249-50 (internal citations  omitted).


25
X-L contends that a genuine issue existed as to  whether it caused the hazardous wastes on  NutraSweet's property (whether there was a  release from X-L's facility). It argues that the  district court's determination that X-L was  partially responsible was based on the expert  testimony of G & M engineers Robert Smith and  James Hill because this testimony was the only  evidence that linked the "mop-bucket dumping at  X-L to the contamination at the NutraSweet site."  Basing summary judgment on this testimony was  erroneous, X-L contends, because its expert,  Shepherd, had a contrary opinion as to the source  of the VOCs.


26
We disagree. The summary judgment concludes that  X-L caused some of the VOCs on NutraSweet's  property, not necessarily all of them. Regardless  of the "battle of the experts," there is not a  genuine dispute that this limited holding was  correct. X-L used solvents in its business that  broke down into the type of VOCs that were found  on NutraSweet's property. In one month alone,  video surveillance captured an X-L employee  dumping waste water eighty-two times on X-L's  property in an area adjacent to NutraSweet's  property. On at least four of these occasions,  the standing wastewater clearly spilled over onto  NutraSweet's property, sometimes forming a fifty-  foot wide pond. NutraSweet tested this  wastewater, soil samples from its property onto  which the wastewater had spilled, and soil  samples from X-L's property where the dumping had  occurred. These tests all revealed the presence  of TCE. With this evidence alone, there is not  even a "metaphysical doubt" that X-L caused at  least some of the VOCs on NutraSweet's property.


27
Further, contrary to X-L's assertion, the expert  opinions are not genuinely in conflict.  Shepherd's conclusions, as to both a lack of a  "chemical fingerprint" for the VOCs and  "groundwater migration," were based on faulty  assumptions. He mistakenly assumed that only one  VOC that X-L used in its business, TCA, was found  on NutraSweet's property. But NutraSweet's expert  showed that all twelve of the VOCs that were  found on NutraSweet's property were also found on  X-L's property. Shepherd also used a problematic  method in analyzing groundwater flow: his  calculations were based on the time of year when  rainwater recharge would give misleading results  on the direction of the flow. By contrast,  NutraSweet's expert minimized the effect of  rainwater recharge. On appeal, X-L does not  dispute these problems with Shepherd's  assumptions and analyses. These defects result in  an expert opinion that is substantially  incomplete if not inaccurate. In any event,  because it does not address (much less  contradict) several matters asserted by  NutraSweet's expert, it cannot create a genuine  issue on whether X-L caused at least some of the  VOCs on NutraSweet's property. See Liberty Lobby,  477 U.S. at 249-50 (summary judgment may be  granted if the evidence "is not significantly  probative").


28
B. Limiting Shepherd's Trial Testimony  Under Fed. R. Civ. P. 37(c)


29
The Federal Rules of Civil Procedure require  parties to file reports of expert witnesses they  intend to use at trial. See Fed. R. Civ. P.  26(a)(2). If a party does not timely file his  reports, the district court may exclude the  party's expert from testifying at trial on the  matters the party was required to disclose. See  Fed. R. Civ. P. 37(c)(1). The sanction of  exclusion is "automatic and mandatory unless the  party to be sanctioned can show that its  violation of Rule 26(a) was either justified or  harmless." Finley v. Marathon Oil Co., 75 F.3d  1225, 1230 (7th Cir. 1996). We review the  district court's exclusion of testimony for abuse  of discretion. See Salgado v. General Motors  Corp., 150 F.3d 735, 739 (7th Cir. 1998).


30
Because X-L did not file a supplemental expert  witness report on the site work at X-L's  property, the district court excluded Shepherd  from testifying about this work and limited his  testimony to his initial expert witness report.  X-L attempts to explain its failure to file a  supplemental expert report by complaining that  NutraSweet used a new expert (Dr. Ball) in its  supplemental report and changed (more accurately,  supplemented) its theory of the case. Assuming  NutraSweet did so (on that, more later), X-L  still fails to explain why this justified its  failure to file a supplemental expert report. The  site work occurred in early October 1997;  NutraSweet filed its test results by the March 4,  1998 deadline (X-L did not); and NutraSweet filed  its supplemental expert witness report of Dr.  Ball ahead of schedule on March 20, 1998. Even  though Ball's report contained new theories, X-L  does not explain why it could not file its  supplemental expert report by the April 10, 1998  extended deadline it requested and received. Nor  does it explain why it could not meet its  proposed, revised May 5 super-extended deadline.  By the time of these deadlines, X-L had had  Ball's report for three weeks and five and one-  half weeks, respectively. Even if Ball's report  was not sufficiently specific (an argument X-L  made below but not here), it should have at least  filed a preliminary supplemental report or told  the court of its concerns with Ball's report by  the April 10 deadline (or certainly by its  proposed May 5 deadline). There was no reason for  it to just sit by for six weeks after the April  10 deadline and do nothing while the trial date  was fast approaching. There appears to be no  justification for X-L's failure to file some sort  of a supplemental report that would have enabled  Shepherd to expand his testimony. See Salgado,  150 F.3d at 741 ("Salgado never offered--indeed,  does not offer to this date--a satisfactory  explanation for its failure to comply with the  directive of the district court").


31
X-L's failure to file a supplemental report also  was not harmless. The district court granted  NutraSweet's Rule 37(c) motion on May 22. At that  time, the court had already postponed the trial  date once. The trial was in less than two months  (on July 14), and the pretrial order was due in  about three weeks (on June 15). Without even a  preliminary or draft supplemental expert witness  report from Shepherd, NutraSweet was greatly  hampered in its ability to examine him about his  analysis of the site work. See Salgado, 150 F.3d  at 742. In these circumstances, the use of the  "automatic" sanction of exclusion was not an  abuse of discretion. Id.

C.  The Trial

32
X-L raises numerous issues regarding the trial.  It first argues that NutraSweet "sandbagged" it  and violated Fed. R. Civ. P. 56(d) by changing  its theory of liability from summary judgment to  trial, where NutraSweet relied on Ball's  additional theories. X-L fails to support its  Rule 56(d) argument with a single case citation  and thus has not properly presented this issue  for appellate review. See Fed. R. App. P.  28(a)(9)(A); United States v. Mason, 974 F.2d  897, 901 (7th Cir. 1992) (failure to cite case  law in support of argument waives appellate  review). Furthermore, X-L did not object below to  Ball's expert witness report, even though it was  on file for months before the trial, and X-L was  fully aware that the report contained new  theories (X-L complained about the new theories  in the report, but it did not move to bar  NutraSweet from using them). Moreover, X-L cannot  complain that it was duped when prior to the filing of Ball's report, it acknowledged that it  knew the report would likely contain additional  theories, but far from objecting, X-L simply  requested that NutraSweet file its supplemental  report first.2 Thus, X-L waived the issue of  Ball's supplemental theories. Consolidated  Bearings Co. v. Ehret-Krohn Corp., 913 F.2d 1224,  1232 n.9 (7th Cir. 1990) (failure to raise  arguments below waived them on appeal).


33
Even if X-L had properly presented this issue,  we would disagree that NutraSweet had pulled a  "bait and switch."3 Recall that at summary  judgment, NutraSweet argued that X-L was at least  partially responsible for the VOCs on its  property due to mop-bucket wastewater ponding  over to its property or leaching into the soil  and then traveling to its property. After summary  judgment, X-L's expert opined in his report that: 1) the amount of VOCs in diluted mop-bucket  wastewater was too small to account for the  substantial deposits of VOCs on NutraSweet's  property; and 2) the type of soil did not allow  the wastewater to migrate in groundwater to  NutraSweet's property. To rebut these theories,  NutraSweet tested the soil on X-L's property. In  doing so, it realized the environmental problem  was much bigger than it had thought:  the testing  indicated that concentrated solvents had been  dumped directly onto X-L's property near  NutraSweet's property. NutraSweet also discovered  that concentrated solvents had been dumped onto  its own property. In response to these findings,  Ball conducted tests (discussed later) which led  him to opine that: 1) the type of soil allowed  solvents to migrate in groundwater from the X-L  site to the NutraSweet site and; 2) direct  dumping of concentrated VOCs had begun on the X-L  site but moved to the NutraSweet site after X-L  had paved its property with a parking lot in the  mid-1970's. Based upon his analyses, Ball  concluded that X-L's activities were the cause of  the VOCs on NutraSweet's property. It was not  inappropriate for NutraSweet to supplement its  theory of the case due to newly-discovered  evidence, and X-L was not unfairly surprised by  NutraSweet doing so (indeed, because NutraSweet  filed Ball's supplemental report months before  the trial, X-L was able to move to bar Ball from  testifying on grounds that his testimony would be  based on speculation, and it objected at trial on  the same ground). Because X-L not only failed to  object that Ball's rebuttal theories would  prejudice it, but stated that all it wanted was  NutraSweet to file its new theories first (note  2, supra), X-L in effect agreed to NutraSweet  proceeding at trial with these theories. See Fed.  R. Civ. P. 15(b); Walton v. Jennings Community  Hosp., Inc., 875 F.2d 1317, 1320 n.3 (7th Cir.  1989) (Rule 15(b) "allows great latitude in  amending complaints to conform with subsequent  changes as the case develops").


34
X-L next complains that Ball's testimony did not  satisfy the standards for admissibility for  expert witnesses. "In deciding whether to admit  the proffered expert testimony, a district court  must be guided by the instructions of Daubert."  Walker v. Soo Line R.R. Co., 208 F.3d 581, 586  (7th Cir. 2000) (citing Daubert v. Merrell Dow  Pharmaceuticals, Inc., 509 U.S. 579 (1993)).  Under the so-called Daubert framework, a district  court must determine whether: (1) the expert  would testify to valid scientific, technical, or  other specialized knowledge; and (2) his  testimony will assist the trier of fact. Fed. R.  Evid. 702; Kumho Tire Co., Ltd. v. Carmichael,  119 S. Ct. 1167, 1174 (1999); Walker, 208 F.3d at  586. "The admission of expert testimony from  technical fields is governed by the same concerns  and criteria as the admission of scientific  expert testimony", but with respect to technical  testimony, the "Supreme Court in Kumho Tire  explained that the Daubert 'gatekeeper' factors  had to be adjusted to fit the facts of the  particular case at issue, with the goal of  testing the reliability of the expert opinion."  United States v. Brumley, 217 F.3d 905, 911 (7th  Cir. 2000) (citing Kumho Tire Co., 119 S. Ct. at  1175). "We review de novo whether the district  court properly followed the framework set forth  in Daubert." Id. If the district court properly  applied the Daubert framework, we review its  decision to admit or exclude expert testimony  only for an abuse of discretion. Kumho Tire Co.,  119 S. Ct. at 1176; Brumley, 217 F.3d at 911.


35
X-L does not argue that the district court  failed to follow the two-part Daubert framework;  rather, it disputes the court's application of  it. Specifically, X-L argues that Dr. Ball's  opinions were not based on reliable methods and  techniques, the first part of the framework. X-L  does not challenge the reliability of solvent  degradation (speciation), chemical  chromatography, or Darcy's equation for  groundwater migration; these are all tested,  well-accepted, and frequently used methodologies  or technologies in the fields of hydrology and  environmental engineering. See Kumho Tire Co.,  119 S. Ct. at 1175 (testing and acceptance of  technique in the relevant field may indicate  reliability). But X-L argues that it is  speculation to look at a sequence of aerial  photos to determine the history of chemical  dumping.


36
Initially, it must be noted that Ball used these  photographs in conjunction with his other tests  as a means of confirming his hypothesis. Ball  first used chromatography to determine that the  same type of VOCs were on the NutraSweet and X-L  sites. The relative stages of decay of the VOCs  on the respective sites, which he determined by  soil degradation or speciation, showed that the  VOCs on the X-L site were much older than those  on the NutraSweet site. And the rate of  groundwater migration of VOCs on the NutraSweet  site, determined by using Darcy's equation,  confirmed their approximate ages. Ball then  analyzed historical photographs of the sites to  further confirm the dumping sequence: the photos  showed that X-L paved over a large part of its  property in the area where concentrated solvents  had been dumped on its property about the time  the other tests (degradation and groundwater  migration) had indicated that concentrated  solvent dumping began on NutraSweet's property.  To Ball, the photographic analysis confirmed his  hypothesis because in his experience people do  not dump solvents on asphalt or concrete (e.g.,  on parking lots) because they eat away at the  material.


37
Furthermore, the district court did not abuse  its discretion in concluding that photographic  analysis is a well-accepted technique in this  area so as to bear a sufficient indicia of  reliability. Nor did it abuse its discretion in  concluding that Ball could interpret the aerial  photos based on his own experiences and  expertise. As noted, "the test of reliability is  'flexible'" when examining an expert's technical  knowledge and the techniques he employs. Id. at  1171. The district court enjoys "the same broad  latitude when it decides how to determine  reliability as it enjoys in respect to its  ultimate reliability determination." Id.  (emphasis in original). Ball testified that  historical analysis of aerial photographs is an  accepted tool in his field and that in fact the  EPA requires the historical analysis of such  photos and has its own team for doing this. The  district court did not abuse its discretion in  concluding that the common and official  acceptance of photographic analysis made it  sufficiently reliable. Id. ("'acceptability' in  the relevant scientific community" is a factor  "which might prove helpful in determining the  reliability of a particular scientific 'theory or  technique'"). Dr. Ball also testified that he had  been interpreting aerial photos for about twenty  years and that he had developed an expertise in  that area. His work experience made his  interpretation of the photos in this case  sufficiently reliable. See Brumley, 217 F.3d at  911-12 (witness's seven years of experience  working in the area gave his opinion sufficient  indicia of reliability even though it was not  based upon an underlying methodology).


38
X-L's second criticism of Dr. Ball's opinion is  that he did not have essentially "direct"  evidence that X-L was the source of the  concentrated dumping on its and on NutraSweet's  property. Nor, X-L argues, did he have  "specialized knowledge" that X-L was the source  of this dumping. True, unlike with the mop-bucket  dumping, Dr. Ball could not point to videotape  directly connecting the contamination to X-L's  activities. But as an expert witness, Dr. Ball  was not required to have direct evidence or a  personal observation that X-L was illegally  dumping VOCs. Contrast Fed. R. Evid. 701  (discussed in United States v. Santos, 201 F.3d  953, 963 (7th Cir. 2000) (rule governing  testimony by lay witnesses does not interdict all  inference drawing by such witnesses, but the  inferences must be tethered to perception, to  what the witness saw or heard)). As an expert  witness, Dr. Ball could use his "specialized  knowledge" of reliable techniques and methods (as  opposed to "specialized knowledge" of the  incident in question) to form an opinion.  Specifically, he could use the chromatography  results to determine that the solvents on  NutraSweet's property were of the same type (were  from the same source) as those on X-L's property.  Through groundwater migration test results, he  could trace some of the concentrated solvents on  NutraSweet's property as migrating from X-L's  property. Through soil degradation, he could  determine the relative ages of the solvents on  the two sites. He could then combine this  information, the aerial photographs, and the fact  that X-L used solvents that would produce the  VOCs found on both properties (and NutraSweet did  not) and come up with a theory (or opinion) as to  where the solvents came from and how they got  there: X-L's activities. See Huddleston v. United  States, 485 U.S. 681, 691 (1988) ("Individual  pieces of evidence, insufficient in themselves to  prove a point, may in cumulation prove it. The  sum of an evidentiary presentation may well be  greater than its constituent parts."). By using  the test results and his experience, Ball could  infer that X-L was the source of the VOCs, even  though he did not have "specialized knowledge"  that it was. Fed. R. Evid. 704(a) (expert opinion  can be based on an inference and can embrace an  ultimate issue); Walker, 208 F.3d at 587 n.2  (noting that subject to an exception in criminal  matters, experts can testify to ultimate issue);  cf. Brumley, 217 F.3d at 912 (expert's opinion  was proper because it was based on his  experience, not on representing to jury that he  possessed any "special knowledge"). This did not  render his opinion speculative. See Brumley, 217  F.3d at 911.


39
X-L's other arguments concern the weight to be  given Ball's testimony, rather than its  admissibility. For example, X-L complains that in  calculating soil degradation, Ball used the data  that G & M's hydrologists obtained from their  testing of the X-L site, rather than using data  that he himself generated. X-L does not, however,  challenge the reliability of the underlying data,  and Ball's use of G & M's data is perfectly  permissible. Fed. R. Evid. 703 ("The facts or  data in a particular case upon which an expert  bases his opinion or inference may be those  perceived by or made known to the expert at or  before the hearing.") (emphasis added); see also  Walker, 208 F.3d at 588 (expert testimony may  rely on the opinions or data of others unless the  testifying expert's opinion is too speculative or  the underlying basis is faulty). X-L also  complains that Ball only visited the site once.  In some circumstances a brief or solitary  examination might indicate a lack of reliability,  see Kuhmo Tire Co., 119 S. Ct. at 1177 (expert  inspected the tire for the first time on the  morning of this deposition), but an expert is not  always required to personally perceive the  subject of his analysis. See Fed. R. Evid. 703;  Walker, 208 F.3d at 591 (physician was allowed to  render expert opinion even though he did not  personally examine the subject). The reliability  of Ball's opinion was largely dependent upon the  data gathered by others, rather than his personal  observation of the site. This data was  verifiable, and Dr. Ball used reliable  methodologies in reaching his opinion. While  "shoddy preparation by an expert might evidence a  lack of professional qualifications," in this  case we are not prepared to say "that the  district court's decision to admit [Ball's]  testimony was an abuse of discretion." Walker,  208 F.3d at 590-91.


40
X-L next disputes the district court's finding  that it was 100% responsible for the wastes on  NutraSweet's property. It first complains that  the district court should have granted its motion  for a directed verdict under Fed. R. Civ. P. 50.  X-L does not, however, develop this argument, and  therefore it is waived. See Fed. R. App. P.  28(a)(9)(A); John v. Barron, 897 F.2d 1387, 1393  (7th Cir. 1990) ("An appellant must not only  raise issues in his brief, he must present them  in a professional fashion. This court is not  obligated to research and construct legal  arguments open to parties, especially when they  are represented by counsel as in this case.").


41
We also disagree with X-L that the district  court's findings were clearly erroneous and that  it should have entered judgment in its favor  after the trial. See Fed. R. Civ. P. 52(a). Under  the "clearly erroneous" standard, a district  court's findings of fact should be affirmed  unless we are "left with the definite and firm  conviction that a mistake has been committed." R.  L. Coolsaet Const. Co. v. Local 150, Int'l Union  of Operating Eng'rs, 177 F.3d 648, 654 (7th Cir.  1999). We have no such conviction here. In  addition to Dr. Ball's opinion and multiple  analyses, the evidence showed that NutraSweet did  not use chlorinated solvents (except for those in  a self-contained parts cleaner that never  leaked), while X-L admitted that it did use  solvents that contained the same VOCs (TCA, PCE,  and their degradation products) that had  contaminated NutraSweet's property. A G & M  investigating engineer testified that there was  no evidence of any other source of the VOCs  besides X-L. Moreover, NutraSweet rebutted X-L's  "alibi" that it had been properly disposing of  hazardous wastes shipping manifests showed that  X-L did not off-site its spent solvents until  December 1990, and X-L did not even proffer a  theory as to who else could have been responsible  for the VOCs on its and NutraSweet's property.4


42
X-L also argues that post-remediation (or clean-  up) test results indicated that NutraSweet did  not effectively clean up its property, and  therefore it violated the EPA's "national  contingency plan" (NCP). See 42 U.S.C. sec. 9607  (a)(4)(B); 40 C.F.R. sec. 300.700(c); PMC, 151  F.3d at 616. NutraSweet's compliance with the NCP  is required for X-L to be liable. See County Line  Inv. Co. v. Tinney, 933 F.2d 1508, 1512 (10th  Cir. 1991) ("Section 107 provides that a person  is only liable for private party response costs  to the extent that these costs were incurred  'consistent with the national contingency plan.'  Proof of response costs incurred 'consistent  with' the NCP is, therefore, an element of the  prima facie private cost recovery action under  CERCLA.") (quoting 42 U.S.C. sec. 9607(a)(4)(B)).  At the summary judgment stage, the district court  determined that X-L was liable to NutraSweet.  NutraSweet, 933 F. Supp. at 1423 ("The court  rules as to the liability prong, but finds a  genuine issue of material fact as to the  attributable damages."). X-L therefore should  have contested the effectiveness of NutraSweet's  clean-up at summary judgment, for if NutraSweet  did not comply with the NCP, then X-L would not  have been liable for any of NutraSweet's clean-up  costs. 42 U.S.C. sec. 9607(a)(4)(B); County Line,  933 F.2d at 1512 ("Evaluation for conformity with  the NCP at [summary judgment] is proper, in order  to determine whether Plaintiffs are entitled to  recover any of their response costs and to avoid  useless trial of the case at a later juncture,  should Plaintiffs fail to show the requisite  consistency.") (emphasis added). Because X-L did  not raise the NCP issue at summary judgment, it  has waived it. See Bruner Corp. v. R. A. Bruner  Co., 133 F.3d 491, 497 (7th Cir. 1998) (defendant  waived right to dispute damage amount because it  failed to raise argument during summary judgment  when issues of liability and damages were being  considered).


43
But even if X-L had preserved that issue, the  district court did not clearly err in concluding  that NutraSweet had satisfied the NCP. The  Illinois EPA approved NutraSweet's clean-up plan,  and the agency monitored the progress of the  remediation. NutraSweet remediated its property  until the Illinois EPA advised it that it could  stop because NutraSweet's efforts had succeeded  to the maximum extent possible. In light of this  evidence, we are satisfied that NutraSweet met  this requirement for a CERCLA recovery.


44
Lastly, X-L contests the amount of damages that  the district court awarded NutraSweet, claiming  that there is insufficient documentation to  support the costs NutraSweet incurred in  investigating and remediating its property. The  amount of NutraSweet's clean-up costs was also  litigated at summary judgment. See NutraSweet,  933 F. Supp. at 1415. There, X-L did not contest  these costs (indeed, X-L did not do so until  after trial when the parties were litigating the  question of pre-judgment interest). As a result,  NutraSweet was entitled to partial summary  judgment on the issue of its costs. X-L cannot  now dispute the accuracy of the amount of  remediation costs; it can only dispute the  percentage of them for which it is responsible.  See id. at 1423 ("X-L is liable for the amount of  response costs attributable to the VOCs  originating from the X-L facility. The extent of  liability, and the resulting amount of  recoverable costs, must be left for trial."). And  as stated, the district court did not clearly err  in finding X-L to be 100% responsible for them.  Therefore, X-L loses on this issue as well.5

IV.  Conclusion

45
Because there is no genuine issue that X-L was  responsible (and hence liable) for some of the  hazardous wastes on NutraSweet's property, the  district court did not err in granting partial  summary judgment to NutraSweet on the issue of  liability. The district court did not abuse its  discretion in excluding X-L's expert from  testifying on the results of the October 1997  site work due to X-L's failure to timely file its  supplemental expert report. The district court  also did not abuse its discretion in determining  that the techniques and methods upon which  NutraSweet's expert based his opinion were  sufficiently reliable. Furthermore, the district  court did not clearly err in finding after trial  that X-L was in fact 100% responsible for the  VOCs on NutraSweet's property and in finding that  NutraSweet complied with the NCP in remediating  (or cleaning up) its property. Lastly, because X-  L did not oppose at summary judgment NutraSweet's  evidence of its clean-up costs, it waived this  issue, and the consequent issue of the amount of  damages.


46
For the foregoing reasons, the judgment of the  district court in favor of the plaintiff is AFFIRMED  in all respects.



Notes:


1
 CERCLA defines a "facility" as, among other  things, "any site or area where a hazardous  substance has been deposited, stored, disposed  of, or placed, or otherwise came to be located."  See sec. 101(9)(B), 42 U.S.C. sec. 9601(9)(B). At  the summary judgment stage, the district court  noted that this case was unusual in that the  contamination of the NutraSweet site was  allegedly due to hazardous wastes being  improperly disposed of on the X-L site and then  migrating over to NutraSweet's property (at  trial, NutraSweet theorized that the wastes were  also due to X-L directly dumping them onto  NutraSweet's property, infra). Because hazardous  wastes had been "deposited," or "otherwise came  to be located" on both NutraSweet and X-L's  property, the district court held that both sites  were "facilities." NutraSweet, 933 F. Supp. at  1417-18 & n.3. Whether or not the district court  was correct to consider both sites as  "facilities," it is indisputable that X-L owned a  facility, because it was its land or business  "from which there [was] a release, or a  threatened release which cause[d] the incurrence  of response costs." See CERCLA Section 107(a). We  therefore consider it irrelevant whether  Nutrasweet also had a "facility," because the  hazardous substances eventually came to rest on  its land.


2
 See Defendants' Motion to Revise Scheduling Order  at 2, para. 4 ("Plaintiffs' initiation of  substantial field investigating work after their  first expert opinion reports were filed strongly  suggests an effort to change and/or add to the  prior-stated opinions. . . . [Plaintiffs] should  first produce any amended or supplementary expert  opinion reports. Defendants will then be in a  position to understand plaintiffs' opinion  evidence (if it has changed in any way as a  result of the later field investigation) and be  able to respond to it with any needed  supplementary expert reports of their own.")  (emphasis in original).


3
 According to X-L, the "bait" was the expert  opinions of the G & E engineers used at summary  judgment and the "switch" was the expert opinion  of Dr. Ball used at trial.


4
 X-L cites various district court decisions that  say that, by itself, evidence that a defendant  generated or used hazardous substances that  contained the same chemical constituents that  were found at a contaminated site does not meet a  plaintiff's burden of proving that the defendant  caused the contamination, nor does the proximity  of the defendant's site to the contaminated site,  nor does the defendant's failure to account for  all of its hazardous waste disposal during the  relevant time frame. But here of course the  district court did not have just a category of  such evidence; it had all these types of  evidence, plus considerably more, to support its  findings. And while, as X-L points out, there was  no "smoking gun" connecting all the VOCs directly  to X-L's activities, there was sufficient  evidence to support the district court inferring  that X-L's activities were the cause of the  contamination.


5
 Because the district court found that X-L was  100% liable for the VOCs on NutraSweet's  property, it awarded NutraSweet its costs under  sec. 107. X-L argues that because Dr. Ball  indicated that some of the VOCs migrated off  NutraSweet's site, NutraSweet is not an innocent  landowner and therefore must recover under sec.  113(f), and that under the evidence, X-L's share  of responsibility would be zero. We reject as  disingenuous this attempt by X-L to exonerate  itself of any responsibility. This one brief  comment in Ball's testimony does not show that  the district court clearly erred in finding X-L  to be 100% responsible for the VOCs on  NutraSweet's property and that NutraSweet was  innocent of the release of any hazardous wastes.  Even if there were a release of VOCs off  NutraSweet's property, we cannot tell on this  record if it was de minimis, in which case  NutraSweet would still be able to recover under  sec. 107 as an innocent landowner. See PMC, 151  F.3d at 616 (sec. 113(f) action) ("PMC's spills  may have been too inconsequential to affect the  cost of cleaning up significantly, and in that  event a zero allocation to PMC would be  appropriate."), and Rumpke, 107 F.3d at 1241  (possible to view a sec. 107 action as an  innocent landowner proceeding under sec. 113(f)  with an "implied claim for contribution, where  the landowner is alleging that its share should  be zero."). Furthermore, if a release of  hazardous materials occurred off of NutraSweet's  property, NutraSweet still might be "innocent" as  to the hazardous wastes that X-L released onto  its property (which is the subject of  NutraSweet's sec. 107 action), and such a release  would not relieve X-L of its liability to  NutraSweet, although it might give another party  a right to recover from either NutraSweet or X-L  or both.


