210 F.3d 760 (7th Cir. 2000)
UNITED STATES OF AMERICA,    Plaintiff-Appellee,v.WILLIAM K. SMITH,    Defendant-Appellant.
No. 99-3326
In the  United States Court of Appeals  For the Seventh Circuit
Argued January 20, 2000Decided April 12, 2000

Appeal from the United States District Court for the  Southern District of Illinois, East St. Louis Division.  No. 99 CR 30044--G. Patrick Murphy, Judge.
Before COFFEY, MANION and ROVNER, Circuit Judges.
ROVNER, Circuit Judge.


1
William K. Smith pled  guilty to charges of conspiring to manufacture  methamphetamine and assaulting a federal officer.  The district court sentenced him to 33 months on  each count, to be served concurrently. In  calculating this sentence, the district court  adjusted Smith's sentence two levels upward  pursuant to U.S.S.G. sec. 3C1.2, for reckless  endangerment during flight. On appeal, Smith  objects to this enhancement on two grounds.  First, he contends the government failed to meet  its burden in proving that he actually endangered  the officers' lives. Second, Smith faults the  district court for relying on personal, extra-  record knowledge instead of record evidence in  making its findings on this enhancement. We  vacate the sentence and remand.

I.

2
One of the substances used in the manufacture  of methamphetamine is anhydrous ammonia, which is  also used in the farming industry as a  fertilizer. Anhydrous ammonia has a boiling point  of 28 degrees below zero, which means that to  store it in a liquid form, it must be kept at  extremely low temperatures or it must be stored  under pressure. On farms, it is typically stored  under pressure, and then injected into the soil  where it combines with the water in the soil to  form a fertilizer. "Anhydrous" means "free from  water" and this same quality which makes  anhydrous ammonia useful in farming renders it  very dangerous to people. When liquid anhydrous  ammonia comes into contact with skin or eyes or  when the vapor is inhaled, it can severely burn  and damage tissues. In sufficient quantities and  concentrations, it can cause death.


3
On the day of Smith's arrest, police officers  had been alerted to a possible methamphetamine  manufacturing operation, and were surveilling  Smith and his co-conspirator Alfred Poppen. The  officers observed Smith and Poppen stop off at an  anhydrous ammonia storage tank at a local farm,  where they apparently obtained some of the  substance in a bucket. After driving a short  distance, Poppen and Smith allegedly transferred  the anhydrous ammonia into a thermos and  continued on to Smith's home. At that time,  officers attempted to stop the vehicle by  activating their lights. Poppen and Smith  continued driving, and began to head out of town.  The two officers continued to follow the car  driven by Poppen. During the pursuit, the  officers saw Smith toss a thermos lid out the  window. One officer observed Smith dumping  anhydrous ammonia out of the thermos through the  rolled down window of the car. The chase took  place on a gravel road and the officers kept a  distance of only five to ten feet between the  vehicles because they did not want the road dust  to obscure their vision of the activity in the  car. One officer reported that the ammonia was in  liquid form as it was being poured out the window  but that it instantly vaporized, creating a cloud  through which the officers then drove in the  course of the pursuit. The officers closed the  vents of their car and ensured that the windows  were closed, and they were not actually injured  by the ammonia dumping. Once the defendants' car  stopped, Smith tried to run from the officers and  attacked one of them as he was being captured,  giving rise to the charge of assaulting a federal  officer.


4
The district court enhanced Smith's offense  level under section 3C1.2 of the Sentencing  Guidelines, and Smith objected to the  enhancement. In sentencing Smith, the court  listened to argument from the government and from  Smith regarding the dangerousness of anhydrous  ammonia. The court considered two reports  published by universities regarding the safe  handling of anhydrous ammonia in the agricultural  setting. Smith's counsel argued that there was no  evidence of the quantity of the substance  released, and no evidence of what quantity would  be harmful under the circumstances in which it  was released, out in the open air during close  pursuit. After hearing argument from Smith's  counsel, the court asked whether counsel had ever  worked on a farm. Smith's counsel replied that  she had not, and the court ruled on Smith's  objection:All right. Thank you. The court understands the  defendant's objection; but, the objection is  overruled. There is--I'm satisfied that you get  a nose full of anhydrous ammonia or a face full  of it, it is dangerous. And I'm not trying to  bring my own personal experience into this; but,  I can't ignore the fact that growing up in the  country I know what anhydrous ammonia is. And  this is very dangerous. It just is.


5
Sentencing Tr. at 9. The court then adopted the  probation officer's position that Smith's dumping  of anhydrous ammonia created a risk of serious  bodily injury. Smith appeals from the two-level  increase on two grounds. First, he contends the  government did not meet its burden of proving the  dangerous nature of anhydrous ammonia in the  quantity and concentrations that he released in  the course of flight from the officers. Second,  he contends that the district court improperly  relied on extra-record knowledge in assessing the  dangerousness of anhydrous ammonia, and the  district judge should have recused himself when  he became aware that he was unable to disregard  his prior knowledge.

II.

6
We review the district court's enhancement for  clear error. United States v. Watson, 189 F.3d  496, 501 (7th Cir. 1999); United States v.  Chandler, 12 F.3d 1427, 1433 (7th Cir. 1994). The  government has the burden of establishing by a  preponderance of the evidence facts which justify  an upward adjustment of the defendant's base  offense level. Watson, 189 F.3d at 502. Section  3C1.2 provides:


7
If the defendant recklessly created a substantial  risk of death or serious bodily injury to another  person in the course of fleeing from a law  enforcement officer, increase by 2 levels.


8
U.S.S.G. sec. 3C1.2.1 Smith argues that  although anhydrous ammonia is a dangerous  substance, there is no evidence in the record  supporting a finding that he created a  substantial risk of death or serious bodily  injury in the quantity and concentration he  released from the car during flight. A defendant  recklessly creates a substantial risk when he is  aware of the risk created by his conduct, and the  risk was of such a nature and degree that to  disregard that risk constituted a gross deviation  from the standard of care that a reasonable  person would exercise. Chandler, 12 F.3d at 1433.  He also contends that the district judge relied  on his own personal knowledge of the  dangerousness of this substance rather than on  any record evidence in reaching his conclusion.  The government contends that we should look to  the dangerousness of the act and not the  consequences of the act in assessing whether  Smith created a substantial risk of death or  serious bodily injury. The government argues that  it was merely fortuitous that the substance  vaporized and did not harm the officers as they  drove through the vapor cloud, and that the  defendant should not benefit from this fortuitous  outcome. The government further maintains that  because Smith did not request that the district  judge recuse himself, Smith waived any claim for  recusal.


9
We begin by reviewing the record to determine  if there is evidence supporting the finding that  Smith's dumping of anhydrous ammonia created a  substantial risk of death or serious bodily  injury to the officers during the pursuit. The  district court adopted the probation officer's  position in rejecting Smith's challenge to the  adjustment. The probation officer's Presentence  Investigation Report ("PSR") recounts the  officers' testimony that during the pursuit,  Smith first tossed a thermos lid out the car  window and then twice dumped anhydrous ammonia  from the thermos. The PSR then concludes that  "[b]ecause the defendant recklessly endangered  law enforcement officials during flight by  dumping anhydrous ammonia out of a window of a  moving vehicle, a two level increase is warranted  pursuant to sec. 3C1.2." In the calculations  section of the report, the PSR repeats that "two  levels are added for reckless endangerment during  flight because the defendant dumped the anhydrous  ammonia out of the car and endangered officers."  The PSR contains no information about the  quantity of anhydrous ammonia dumped, the  quantity the thermos could hold, what  concentration and duration of exposure to ammonia  vapor is harmful, what concentration and duration  of exposure the officers experienced during the  chase, how fast the vehicles were traveling, the  weather conditions that day and the effect of the  temperature on the vaporizing of the substance,  and what harm was likely given the circumstances  of the dumping.


10
In objecting to the enhancement, Smith submitted  two reports, culled from the Internet, regarding  the safe handling of anhydrous ammonia in the  farm setting. Much of the information in these  reports addresses the special harms posed by the  storage of ammonia under pressure. Leaks in  equipment or improper handling can result in  blasts of the substance hitting the skin or eyes  in liquid form, which can result in severe tissue  damage. In some circumstances, vapors can damage  the skin and eyes as well. Persons trapped in a  confined space with vapors of anhydrous ammonia  can seriously damage their lungs, and exposure to  vapors of certain concentrations for certain  durations can cause death. The reports are quite  precise in detailing the potential harms of  anhydrous ammonia vapor. Five parts per million  may cause nose irritation after five minutes of  exposure. Seven hundred parts per million causes  coughing, and also causes eye irritation that can  lead to partial or total loss of sight if not  treated. Two thousand parts per million will burn  and blister skin after only a few seconds of  exposure, and five thousand parts per million  will cause death by suffocation within minutes.  The record thus contains substantial evidence  that anhydrous ammonia is a dangerous substance,  and that under certain conditions it can cause  death or serious bodily injury.


11
What is missing here is what amount Smith  dumped, what concentration of vapors the officers  were exposed to, and for what length of time that  exposure lasted. The government candidly admitted  at oral argument that it did not produce evidence  to the district court of the amount of ammonia  the thermos could hold, or how much ammonia was  in the thermos. Nor does the record indicate the  weather, or the speed of the cars, or any way to  calculate what concentration of vapors the  officers experienced during the pursuit. Indeed  the record does not reveal how it was physically  possible for Smith to transfer first to a bucket  and then to an ordinary thermos a substance that  vaporizes at temperatures above 28 degrees below  zero.


12
Contrary to the government's assertion that any  dangerous act will suffice to meet the standard  of section 3C1.2, the act must create a  substantial risk of death or serious bodily harm.  We know, for example, that fire is dangerous,  that it can cause death or serious bodily harm.  But if Smith had tossed a lighted match out the  car window during the chase, no one would  seriously argue that that action created  substantial risk of death or serious bodily harm.  Here, we do not know if Smith poured the  equivalent of a lighted match out the window, or  if he poured out an amount that would expose  passengers in another car following closely  behind to a substantial risk. The district court  stated that if a person gets a "nose full" or a  "face full" of anhydrous ammonia, the danger for  serious harm exists. The question is whether  Smith released enough of the substance under the  circumstances for that to occur. Because the  government has not met its burden of proving by  a preponderance of the evidence that Smith  created a substantial risk of death or serious  bodily harm to the officers, we vacate the  sentence and remand for proceedings consistent  with this order.


13
Smith also contends that the district court  should have recused itself under 28 U.S.C. sec.  455. That section provides:


14
(a) Any justice, judge, or magistrate of the  United States shall disqualify himself in any  proceeding in which his impartiality might  reasonably be questioned.


15
(b) He shall also disqualify himself in the  following circumstances:


16
(1)  Where he has a personal bias or prejudice  concerning a party, or personal knowledge of  disputed evidentiary facts concerning the  proceeding. . . .


17
However, Smith failed to properly appeal the  court's refusal to recuse under section 455(a).  "[T]he denial of a request that the judge recuse  himself under section 455(a) must be appealed  immediately by application for writ of mandamus,  or it is waived." United States v. Horton, 98  F.3d 313, 316 (7th Cir. 1996); United States v.  Balistrieri, 779 F.2d 1191, 1205 (7th Cir. 1985),  cert. denied, 475 U.S. 1095 (1986). It is less  clear under our case law whether we may review a  refusal to recuse under section 455(b) when the  argument is raised for the first time on appeal.  Edgar v. K.L., 93 F.3d 256, 257 (7th Cir. 1996),  cert. denied, 519 U.S. 1111 (1997) (delay in  seeking disqualification can be fatal but passage  of time is not conclusive if the justification  for disqualification is compelling); Hook v.  McDade, 89 F.3d 350, 353 n.2 (7th Cir. 1996),  cert. denied, 519 U.S. 1071 (1997) (petition for  writ of mandamus is the only recourse available  to challenge a judge's denial of a motion for  disqualification under section 455). Assuming for  the sake of argument that we may appropriately  review a section 455(b) claim raised for the  first time on appeal, we will review for clear  error when the claim is based on the judge's  personal knowledge and the party moving for  recusal is aware of the existence of the ground  for recusal at the time the case is still before  the trial court. See Baldwin Hardware Corp. v.  Franksu Enterprise Corp., 78 F.3d 550, 557 (Fed.  Cir. 1996), cert. denied, 519 U.S. 949 (1996);  United States v. Bosch, 951 F.2d 1546, 1548 (9th  Cir. 1991), cert. denied, 504 U.S. 989 (1992);  Osei-Afriyie v. Medical College of Pennsylvania,  937 F.2d 876, 886 (3rd Cir. 1991). Here, the  district judge admitted that he "can't ignore the  fact that growing up in the country I know what  anhydrous ammonia is. And this is very dangerous.  It just is." That appears to be an admission that  the court may have ruled, at least in part, on  the basis of personal knowledge. However, all of  the evidence in the record is consistent with the  district judge's personal belief, and Smith  himself agrees that anhydrous ammonia is a  dangerous substance. Thus, we fail to see how  Smith was harmed by the court's reliance, if any,  on personal knowledge of the dangers of this  substance. In fact, the dangerousness of the  substance was not a fact under dispute and  arguably the rule does not apply at all. We do  not think the judge clearly erred by not recusing  sua sponte when he became aware that he had some  extra-record knowledge regarding anhydrous  ammonia. To hold otherwise would require the  recusal of every judge who owns a hunting rifle,  for example, when the issue of the dangerous  nature of firearms is before the court. That is  not the kind of personal knowledge of disputed  facts that the rule was meant to protect against.  On remand, we have no doubt that the court will  make is fact findings on the basis of the  evidence in the record before it.


18
VACATED AND REMANDED.



Notes:


1
 The Application Notes to section 3C1.2 specify  that "another person" includes any person other  than a participant in the offense who willingly  participated in the flight. Therefore, we do not  consider whether Smith exposed his co-defendant  Poppen to a substantial risk of death or serious  bodily injury by pouring the anhydrous ammonia  out the window.


