opinion: NATHANIEL R. JONES, Circuit Judge.
  The plaintiff-appellant, Neal Roland, appeals from the district court’s order granting summary judgment to the defendants-appellees. Roland also challenges the court’s award of costs to the defendants. For the following reasons, we find that the court erred in its grant of summary judgment. Thus we reverse and remand this case for further proceedings consistent with this opinion. In addition, the court’s award of costs to the defendants is vacated.
  I.
  The plaintiff-appellant, Neal Roland, is a prisoner at the State Prison of Southern Michigan (“SPSM”), located in Jackson, Michigan. He claims that on November 30, 1983 he was raped in his cell by prisoner Frankie Lee Weatherspoon while Daniel Perry, another SPSM prisoner, served as a lookout. The defendants-appellees are Perry Johnson, the Director of the Michigan Department of Corrections; Dale Foltz, the Warden of SPSM; Thomas Phillips, the Administrative Assistant to Warden Foltz; and Bernard Toland, the Director of Job Classifications for SPSM. Roland’s action, filed pursuant to 42 U.S.C. § 1983 (1982), alleges that the above defendants violated his eighth and fourteenth amendment rights by failing to provide him with adequate safety and protection and by allowing conditions to exist at the prison which resulted in his rape.
  Plaintiff sets forth, in his complaint, certain relevant factual allegations. Those allegations are reproduced below. Many of these allegations, however, are disputed by the defendants.
  Roland, at the time of the alleged rape, was in SPSM for the offense of breaking and entering. His complaint states that since he is a male with “youthful features” and a slight build, he was a likely target for homosexual predators in SPSM. He allegedly has no history of assaultive or violent behavior and was classified by SPSM as requiring only “medium” custody. In April 1983, he had been recommended for a transfer to the Muskegon Correction Facility; but the transfer had not occurred at the time of the alleged rape because of a medical problem.
  Roland’s alleged assailant, Frankie Lee Weatherspoon, is serving life without parole for murder, and the alleged lookout, Daniel Perry, is in prison for first degree criminal sexual conduct and armed robbery. Roland alleges that both Weather-spoon and Perry were known sexual predators and highly assaultive individuals. He further points out that both men were classified by the prison as requiring “close” (one level above “medium”) custody.
  At the time of the alleged rape, all three of these individuals — Roland, Weather-spoon, and Perry — were housed in 11 Block, an “honor block” in which residents are given more privileges, including more out of cell time, than in other cell blocks. To qualify for admission to 11 Block prior to August 1983, an inmate was required to refrain from major misconduct for twelve months and minor misconduct for six months. In August 1983, however, 11 Block was changed from a close custody prison block to a lower, medium custody level. While normally medium and close security inmates are not housed together, when 11 Block was changed in August 1983, certain close security inmates (including Weatherspoon and Perry) were allowed to remain, along with the medium custody prisoners.
  Within 11 Block, Perry and Weather-spoon were classified as “block help” or “porters.” This position gave them added mobility throughout the cell block, including the ability to get out of their cells before other inmates. Perry and Weather-spoon were further sub-classified as “breakmen” and were therefore able to walk up to each tier of 11 Block and operate the mechanical devices of that tier which open the cells of the other inmates. According to Roland, the breakman position was one of “high honor” and should not have been awarded to inmates like Weatherspoon and Perry who, as known sexual predators, were likely to abuse the privilege. Indeed, Roland claims that it is because Weatherspoon and Perry were accorded these positions that they were able to gain access to his cell on the fourth tier of the block. Further, Roland claims that it was this access which allowed Weather-spoon to rape him while Perry served as the lookout.
  To establish the liability of the defendants under section 1983, Roland attempts to show that they were “deliberately indifferent” to his safety, and that this indifference resulted in his rape. As to defendant-appellee Toland, Roland alleges that Toland manifested a deliberate indifference by refusing to reclassify and remove Weatherspoon and Perry from their job assignments as breakmen after being requested to do so by Richard Thrams, the Assistant Resident Unit Manager of 11 Block. Toland, as the Classification Director for SPSM, had the power and responsibility to assign and remove prisoners from their jobs. In making a decision relating to a job assignment, Toland was also to work in coordination with unit managers such as Thrams.
  Roland contends that the facts demonstrate that Thrams requested Toland to reclassify Weatherspoon and Perry because of investigative reports linking them to an ongoing homosexual pressure gang in 11 Block, and because of hearsay evidence that Weatherspoon and Perry were pressing other inmates in the block for sex. Roland contends that the evidence of Weatherspoon and Perry being homosexual predators is consistent with the evidence in their records, both in and out of prison.
  In his deposition, Toland acknowledges that sexual predators should not be block protecters. However, he argues that there was nothing in Weatherspoon’s file to indicate that he had predatory tendencies and that Perry’s file is irrelevant because Perry is not accused of assaulting Roland. Further, Toland argues that the record does not support Roland’s contention that To-land knew, at the time of the rape, that Weatherspoon and Perry were actively pressing other inmates for sex. Finally, Toland suggests that he did not reclassify Weatherspoon and Perry because there was no written documentation or disciplinary finding regarding their alleged behavior in 11 Block. Also, he points out that Thrams himself acknowledged that the information he gave to Toland was not sufficiently trustworthy to be reduced to writing.
  The basis of Roland’s allegations against defendant-appellaee Phillips, the Administrative Assistant to the Warden, is that his (Roland’s) mother, Mrs. Jean Berry, met with Phillips in the summer or fall of 1983 and notified him that her son was in danger of being assaulted by homosexual predators. Phillips denies meeting with Mrs. Berry or discussing any such matter, although he does acknowledge an August 24, 1983 phone conversation with Mrs. Berry regarding Roland’s transfer to the Muske-gon Correction Facility. Mrs. Berry, however, testified in her deposition that she showed Phillips a photograph of her son and told Phillips that some inmates were pressuring her son for sex. She testified that Phillips replied that if her son was not a homosexual, he had nothing to worry about.
  Roland also asserts that Phillips was aware of a November 1983 investigation which included allegations by certain inmates against Perry and Weatherspoon relating to sexual pressuring. Therefore, Roland concludes that Phillips had actual knowledge of the risk to him of an assault, yet took no action to protect him. This failure to act, according to Roland, manifested a deliberate indifference to his security needs.
  Finally, Roland asserts á deliberate indifference on the part of defendants-appel-lees Johnson (the Director of the Michigan Department of Corrections) and Foltz (the Warden of SPSM) to the existence of a pervasive and unreasonable risk of harm to individuals, like Roland, who fit the known profile of prison rape victims. These two defendants are responsible for the rules and policies affecting the operation of SPSM. According to Roland, they are liable for their failure to implement adequate policies which would have protected Roland and others like him in an atmosphere of unreasonable and pervasive sexual pressures. Roland also claims that their approval of, or acquiescence, in the policies on job classification and admission to 11 Block solidifies their liability. Further, Roland alleges that Johnson and Foltz failed to set up policies which would allow inmates like Weatherspoon and Perry to be screened out of the honor block based on general behavioral problems or reliable information from inmate sources, short of the need for an actual misconduct hearing and finding. Foltz and Johnson are also alleged to be responsible for a pervasive policy at SPSM which discourages reporting and prosecution of sexual assaults, since those who report that they have been assaulted are placed in protective custody which limits inmates in a manner similar to punitive detention. Finally, Roland claims that Foltz and Johnson were on notice that sexual assaults were a serious problem at SPSM but failed to issue a policy that would protect individuals likely to be victimized. To establish notice, Roland points to several reports that were available to Foltz and Johnson and which document the problems of physical and sexual assaults at SPSM as well as the existence of policies discouraging the reporting of such assaults.
  Defendants Foltz and Johnson counter Roland’s allegations by arguing that since Roland never told anyone that he had been threatened by Weatherspoon, they could not be aware that he might be in jeopardy. Furthermore, they assert that the policy of protective custody does not discourage the reporting of assaults, and that they have actively sought ways to eliminate violent activity at SPSM.
  Roland filed this lawsuit on November 16, 1984, in the United States District Court for the Eastern District of Michigan. After discovery began, the district court, on June 17, 1985, assigned the case to Magistrate Steven Pepe for a report and recommendation pursuant to 28 U.S.C. § 636(b)(1)(B) (1982). Subsequent to that assignment, the court, on June 26, 1985, pursuant to 28 U.S.C. § 636(b)(2), entered an order instructing the magistrate to serve as a special master for the case and, upon the parties’ consent, conduct the trial. The parties consented to a trial before the magistrate with the express understanding that it would be a jury trial. Thereafter, discovery continued and was apparently completed when, on December 19,1985, the defendants moved for summary judgment.
  The magistrate conducted hearings on the defendants’ motion and, on June 12, 1986, in an 88-page opinion, recommended that the motion be denied and the case proceed to trial. In the magistrate’s view, there was sufficient evidence from which a jury could find that the defendants were deliberately indifferent to the safety needs of the plaintiff. Therefore, Magistrate Pepe felt summary judgment was an inappropriate resolution of this case.
  The defendants filed timely objections to the magistrate’s recommendation with the district court. On July 10, 1986, the district court, Judge LaPlata presiding, granted the defendants’ motion for summary judgment. In the court’s 2lk page order of dismissal, the magistrate’s report was neither mentioned nor discussed. In the court’s view, the plaintiff had, at most, only established that the defendants were negligent in permitting Weatherspoon and Perry to serve as block porters. Further, the court found that the record was devoid of any proof that prison authorities were aware of specific threats directed at Roland by his alleged assailants. Finally, in an order dated August 18, 1986, the district court awarded defendants their costs for deposition transcripts. This appeal, which was timely filed, challenges both of the district court’s orders.
  II.
  The first issue we address is plaintiff’s argument that the district court committed reversible error in not affording any weight to the report and recommendation of the magistrate. In Roland’s view, the magistrate’s recommendation that summary judgment was inappropriate should have been reviewed by the district court under the “clearly erroneous” standard, and therefore, the district court erred in reviewing the report de novo. For the following reasons, we find this argument to be without merit.
  The district court’s June 26, 1985 order, assigning this case to Magistrate Pepe, is set forth below:
  Pursuant to Tile [sic] 28 U.S.C. Section 636, IT IS HEREBY ORDERED that the above entitled cause is assigned to the docket of Magistrate Steven D. Pepe, United States Magistrate for all pretrial and appropriate hearings under 636(b)(1)(A) and (B). Magistrate Pepe is further appointed as special master under 636(b)(2) and Fed.R.Civ.P. 53 and upon consent of the parties, may try the matter at the earliest available date and thereafter file a report and recommendation with the district judge.
  J. App. at 133 (emphasis added).
  This order was issued subsequent to the court’s June 17, 1985 order assigning the case to Magistrate Pepe, pursuant to 28 U.S.C. § 636(b)(1)(B), for a report and recommendation. Thus, it appears that Magistrate Pepe received this case from the district court via two different referrals. The question is what standard of review should be applied by a district court when there has been a referral under both section 636(b)(1)(B) and 636(b)(2).
  28 U.S.C. § 636 sets forth both the jurisdiction and powers of United States magistrates. A referral to a magistrate pursuant to 28 U.S.C. § 636(b)(1)(A) and (B) authorizes the magistrate to rule on both non-dispositive and dispositive pretrial motions. A referral pursuant to 28 U.S.C. § 636(b)(2) authorizes the magistrate, as a special master, to conduct a trial upon the consent of the parties. The standard of review applicable to a magistrate’s recommendation is dependent upon which of these sections grants his authority in a particular instance. Here, the magistrate has ruled on a summary judgment motion which, according to section 636(b)(1)(B), is a dispositive pretrial motion and one which is subject to de novo review. See Brown v. Wesley’s Quaker Maid, Inc., 771 F.2d 952, 954 (6th Cir.1985), cert. denied, 479 U.S. 830, 107 S.Ct. 116, 93 L.Ed.2d 63 (1986); EEOC v. Keco Industries, Inc., 748 F.2d 1097, 1102 (6th Cir.1984). A summary judgment determination should be distinguished from section 636(b)(1)(A) determinations, which are subject to a clearly erroneous standard of review. To make the issue even more complicated, a special master’s findings, pursuant to section 636(b)(2), are reviewed under both the clearly erroneous standard (factual findings) and the de novo standard (mixed or pure findings of law). See Oil, Chemical and Atomic Workers International Union, AFL-CIO v. NLRB, 547 F.2d 575, 580 (D.C.Cir.1976), cert. denied sub nom., Angle v. NLRB, 431 U.S. 966, 97 S.Ct. 2923, 53 L.Ed.2d 1062 (1977). Thus, the standard of review applicable to a special master’s findings depends on (1) which section grants the magistrate’s authority in a particular instance and (2) whether the finding is one of fact or of law.
  After sorting through the statutory provisions, we find that the district court was correct in reviewing de novo the magistrate’s decision as to summary judgment. The summary judgment motion was a section 636(b)(1)(B) dispositive motion which is subject to de novo review. To hold that the designation of a magistrate as a special master changes the court’s standard of review as to a magistrate’s recommendation on a dispositive motion would allow a district court to avoid the classification of subsections (b)(1)(A) and (B) simply by designating a magistrate as a special master. Therefore, we refuse to engage in such reasoning. Although it would have been preferable for the district court to have listed its reasons for rejecting the magistrate’s opinion, such action was not required because the review was de novo. Thus, Roland’s contention as to this point is without merit.
  III.
  Having resolved the procedural issue in a manner favorable to the defendants-appellees, we must now determine whether the court’s summary judgment order is also to be upheld. This court may only sustain a grant of summary judgment if the materials before the district court show that there is no genuine issue as to any material fact and that the moving party is entitled to judgment as a matter of law. Furthermore, all evidence must be viewed in a light most favorable to the non-moving party. See Sec. & Exch. Comm’n v. Blavin, 760 F.2d 706, 710 (6th Cir.1985) (per curiam). Applying this standard to the facts of this case, we find the district court improperly granted summary judgment to the defendants.
  The parties do not dispute that the legal standard applicable to determining whether a violation of the eighth amendment occurred in the context of an assault upon an inmate is whether the defendants’ conduct amounted to a “deliberate indifference” to a risk of injury to the plaintiff. See Whitley v. Albers, 475 U.S. 312, 106 S.Ct. 1078, 1084, 89 L.Ed.2d 251 (1986); Estelle v. Gamble, 429 U.S. 97, 104, 97 S.Ct. 285, 291, 50 L.Ed.2d 251 (1976). The Supreme Court in Whitley concluded that in order to support an action under section 1983, plaintiffs must establish something more than a lack of ordinary due care, inadvertence or error. Instead, the conduct must be “obdurate” or “wanton,” i.e., a recklessness or callous neglect. Whitley, 106 S.Ct. at 1084. This standard is designed to strike an appropriate balance between the deference that should be accorded to prison officials in their administration of the prison and the constitutional right of prisoners to be free from cruel and unusual punishment. Id.
  In this case, Roland has assembled a substantial record establishing a legitimate factual question as to whether the defendants were deliberately indifferent to his safety. This is especially true since all factual inferences are to be resolved in his favor on a motion for summary judgment. Consequently, when viewing the evidence in a light most favorable to the plaintiff, as we must do, we conclude that it is possible that a jury could have found liability as to each of the defendants on the following bases.
  First, as to defendant Toland, a jury could find that he had been informed of the threat Weatherspoon and Perry posed to other inmates, but failed to take action to reclassify these inmates from their positions as breakmen when asked to do so by Assistant Resident Unit Manager Thrams. A jury could also find that if Toland had conducted further investigations after his discussions with Thrams, he would have found widespread evidence that Weather-spoon and Perry were pressing other inmates for sex.
  Second, as to defendant Phillips, a jury also could find that he had been warned by plaintiffs mother, Mrs. Berry, that her son had been pressured by other inmates for sex. The jury could also find that Mrs. Berry showed Phillips a picture of her son which would suggest that he fit the known profile of prison rape victims. Finally, a jury could find that Phillips’ response to Mrs. Berry, i.e., that her son need not worry if he was not a homosexual, was effectively a failure to act and therefore manifested a deliberate indifference to the plaintiff’s security needs.
  Finally, as to defendants Johnson and Foltz, a jury could find that they were responsible for a pervasive policy at SPSM which discourages the reporting and prosecution of assaults. The jury also could find that despite their knowledge of a high level of violence and sexual assaults at the prison, they failed to adopt policies that would eliminate or control these problems, thereby ensuring the safety of prisoners like Roland. Finally, the jury could find that Johnson and Foltz allowed policies to exist which permitted inmates like Weather-spoon and Perry to hold positions of “hon- or” in a medium security block.
  In light of the above observations, there clearly exist questions of material fact concerning the behavior of each of the defendants with respect to the injuries allegedly suffered by the plaintiff, and whether that behavior under the circumstances of this case amounts to a deliberate indifference to the plaintiff’s safety. Accordingly, a summary judgment order was not appropriate in this case.
  IV.
  Finally, because the district court’s decision is reversed and this case is remanded for trial, the court’s decision to award costs to the defendants is vacated.
  Therefore, for all of the foregoing reasons, the district court’s summary judgment order is REVERSED and this case is REMANDED for further proceedings consistent with this opinion and the court’s award of costs to the defendants is VACATED.
  . Section 636(b)(1)(A), (B), and (C) provide as follows:
  (A) [A] judge may designate a magistrate to hear and determine any pretrial matter pending before the court, except a motion for ... summary judgment.... A judge of this court may reconsider any pretrial matter under this subparagraph (A) where it has been shown that the magistrate’s order is clearly erroneous or contrary to law.
  (B) [A] judge may also designate a magistrate to conduct hearings, including evidentiary hearings, and to submit to a judge of the court proposed findings of fact and recommendations for the disposition, by a judge of the court, of any motion excepted in subparagraph (A), [i.e., summary judgment motions,]....
  (C) [T]he magistrate shall file his proposed findings and recommendations under subpar-agraph (B) with the court and a copy shall forthwith be mailed to all parties.
  Within ten days after being served with a copy, any party may serve and file written objections to such proposed findings and recommendations as provided by rules of court. A judge of the court shall make a de novo determination of those portions of the report or specified proposed findings or recommendations to which objection is made. A judge of the court may accept, reject, or modify, in whole or in part, the findings or recommendations made by the magistrate. The judge may also receive further evidence or recommit the matter to the magistrate with instructions.
  (Emphasis added).
  . Section 636(b)(2) provides as follows:
  A judge may designate a magistrate to serve as a special master pursuant to the applicable provisions of this title and the Federal Rules of Civil Procedure for the United States district courts. A judge may designate a magistrate to serve as a special master in any civil case, upon consent of the parties, without regard to the provisions of rule 53(b) of the Federal Rules of Civil Procedure for the United States district courts.
instruction: What follows is an opinion from a United States Court of Appeals. You will be asked a question pertaining to issues that may appear in any civil law cases including civil government, civil private, and diversity cases. The issue is: "Did the court's ruling on an issue arising out of an alternative dispute resolution process (ADR, settlement conference, role of mediator or arbitrator, etc.) favor the appellant?" Answer the question based on the directionality of the appeals court decision. If the court discussed the issue in its opinion and answered the related question in the affirmative, answer "Yes". If the issue was discussed and the opinion answered the question negatively, answer "No". If the opinion considered the question but gave a mixed answer, supporting the respondent in part and supporting the appellant in part, answer "Mixed answer". If the opinion does not discuss the issue, or notes that a particular issue was raised by one of the litigants but the court dismissed the issue as frivolous or trivial or not worthy of discussion for some other reason, answer "Issue not discussed". If the opinion considered the question but gave a "mixed" answer, supporting the respondent in part and supporting the appellant in part (or if two issues treated separately by the court both fell within the area covered by one question and the court answered one question affirmatively and one negatively), answer "Mixed answer". If the opinion either did not consider or discuss the issue at all or if the opinion indicates that this issue was not worthy of consideration by the court of appeals even though it was discussed by the lower court or was raised in one of the briefs, answer "Issue not discussed".