concurring in part and dissenting in part.
I concur in the judgment reversing Defendants’ convictions on the wire fraud, mail fraud, and smuggling counts on the grounds that Mr. Smith’s testimony was both improper and prejudicial. I do not, however, join in those parts of the court’s opinion concluding that the jury instruction regarding “waste” was proper under Colorado law and satisfied federal constitutional due process. In addition, I dissent from the court’s judgment affirming Mr. Richter’s obstruction of justice conviction. In my view, the flawed jury instruction and the government’s impermissibly broad theory of “waste” require reversal of the wire fraud, mail fraud, smuggling, and obstruction convictions.
A. The Waste Instruction
According to the court, the Waste Instruction was an accurate statement of governing Colorado law. It sidesteps the issue whether it was appropriate to incorporate the Department’s informal interpretation into the instruction, instead con-eluding that the resulting instruction was proper given a regulatory ambiguity and general legislative intent. The court’s conclusion, however, is premised upon its erroneous conclusión that the governing regulation, Part 273.2(f)(3), is ambiguous, thus permitting a court to consult external aides to discern a broader legislative purpose. I disagree with the court’s view of statutory ambiguity and would hold that the district court’s Waste Instruction was not a correct statement of governing Colorado law.
Everyone agrees that Part 273.2(f)(3) of Colorado’s hazardous waste regulations was the proper starting point for the district court. In relevant part, the regulation provides that an electronic device or component (such as a cathode ray tube) becomes a “waste” “on the date the recy-cler determines that the device [or component] cannot be resold, donated, repaired, or refurbished,” or otherwise determines that the device or component cannot be “directly reuse[d]” or resold for its usable parts.
The court concludes that this language is “susceptible to multiple valid interpretations” — one which contains an “original intended purpose” requirement and one which does not. Ct. Op. 1185-87. It reasons that the words “repair” and “refurbish” suggest the regulation contains such a requirement. Finding the regulatory *1202language ambiguous, then, the court holds that the legislative intent of Colorado’s hazardous waste program makes clear that Part 273.2(f)(3) exempts from the definition of “waste” only those electronic devices or components that can be resold, donated, repaired, or refurbished for their “original intended purpose.” I disagree.
I see nothing ambiguous about Part 273.2(f)(3)’s plain language. By the regulation’s plain terms, a device or component is not “waste” if it can be resold, donated, repaired, or refurbished. These terms are disjunctive, and therefore a device or component is not “waste” if a recycler determines that he can do any of those four things with the item (resell it, donate it, repair it, or refurbish it). And because several of these terms have no suggestion of an original use requirement, the jury should have been instructed on the plain language of the regulation: electronic devices and components are “waste” only if a recycler determines that those dévices and components cannot be resold, donated, repaired, or refurbished.
Under the court’s view, however, statutory language is ambiguous when an additional requirement, term, or limitation not contained in the statute’s express language can be consistently added to the relevant language. This view has both practical and legal flaws. From a practical perspective, this view would find ambiguity in nearly every statute or regulation; additional requirements can almost always supplement express terms. From a legal perspective, this view is inconsistent with Colorado law, which holds that courts “cannot supply the missing language and must respect the legislature’s choice of words.” Turbyne v. People, 151 P.3d 563, 568 (Colo.2007); see also People v. Diaz, 347 P.3d 621, 625 (Colo.2015) (“The construction of the majority below requires us to add words — that is, to read the phrase ‘at the time of the assault’ into the statute. But, in interpreting a statute, we must accept the General Assembly’s choice of language and not add or imply words that simply are not there.” (internal quotation marks and citation omitted)).
It is only by adhering to its broad theory of ambiguity that the court can conclude that “the regulation can also be reasonably interpreted to include an original intended purpose requirement.” Ct. Op. 1185. It argues its analysis is supported by People v. Disher, 224 P.3d 254 (Colo.2010), and People v. Madden, 111 P.3d 452 (Colo.2005). Again, I disagree.
In Disher, the Colorado Supreme Court rejected the defendant’s argument that the phrase “intimate relationship” necessarily required a sexual relationship. 224 P.3d at 256. Although the court eventually turned to legislative history to confirm its reading of the relevant statute, it first noted the statute’s plain language did not support the defendant’s argument and stated that it would not “read language into the statute that is not there.” Id. In essence, the court rejected the defendant’s request to do precisely what the government attempts to do here: add a requirement to the express statutory language. Id. In Madden, too, the court looked to legislative history to resolve an ambiguity in Colorado’s “prostitution of a child” statute. 111 P.3d at 459. There, however, the statutory definition strongly suggested that such “prostitution” might not require a commercial transaction, a meaning which would conflict with the common understanding of that term. Id. at 458-59. Thus, the court noted that strictly adhering to the statute’s plain language would (a) conflict with the “plain and ordinary *1203meaning” of the term “prostitution,” id. at 458-59, and (b) render the entire statute unnecessary because, without a commercial transaction element, the statute would be transformed into a general sexual assault statute, id. at 460 & n. 14. In this case, however, giving effect to Part 273.2(f)(3)’s plain language would neither create an internal conflict in the regulation’s language nor render the regulation superfluous.
Although the court disclaims any reliance on the Department’s Guidance Document by concluding that the “original intended purpose” requirement is discernible from general legislative intent — a conclusion I take issue with — this case is most analogous to Tebbetts v. Whitson, 956 P.2d 639 (Colo.Ct.App.1997). Teb-betts involved an administrative challenge to an inmate disciplinary hearing, where the inmate was charged with and sanctioned for possessing unauthorized legal papers. Id. at 640. The relevant regulation prohibited inmates from possessing “official papers or documents” but expressly exempted from this general prohibition documents related to judicial or administrative proceedings. Id. at 641-42. The correctional facility narrowly interpreted this exemption, however, finding that it exempted only legal documents related to the inmate himself; the documents possessed by Tebbetts pertained to the legal affairs of other inmates, not his own.
The state appellate court began by observing that agency interpretations are “generally entitled to great deference.” Id. at 641. Despite that observation, the court vacated the inmate’s discipline, finding that the plain language of the regulation controlled. First, the court noted that “the [regulation] on its face does not limit an inmate to possession of his or her own papers.” Id. at 642. Whether an additional limitation could consistently be added to the express terms of the regulation was of no consequence. And second, the court relied on the fact that a separate regulation provided that offenses would be defined only by reference to published regulations. Id.
This case is strikingly similar to Teb-betts. For starters, the governing regulation, Part 273.2(f)(3), “on its face does not limit” permissible reuses of electronic devices and components to reuses only for an “original intended purpose.” Tebbetts, 956 P.2d at 642. That requirement is nowhere to be found in the plain and unambiguous text of the regulation. And second, separate Colorado statutes make clear that agencies’ informal interpretations do not carry the force and effect of a rule. Colo. Rev.Stat. § 25-6.5-102(2), which appears in the same sub-title of the Colorado code as the hazardous waste regulations, provides that informal policy statements and guidance “relating to the implementation, administration, and enforcement ” of hazardous waste regulations do not carry the “force and effect of a rule.” (emphasis added). Only rules promulgated pursuant to the state’s Administrative Procedure Act are given binding effect. Id. That Act, in turn, provides that when the APA’s formal rule-making requirements are bypassed in favor of less cumbersome procedures, agencies’ “interpretative rules or general statements of policy” are not binding. Id. § 24-4-103(1). I therefore think Tebbetts is persuasive and conclude the Colorado Supreme Court would not have supplemented the regulatory language because (a) that language is plain and unambiguous and (b) several express legislative directives prohibit courts from giving legal effect to non-binding, informal agency interpretations.
*1204Finally, this court justifies its conclusion by stating that Defendants’ interpretation of Part 273.2(f)(3) “would create a defect in Colorado’s hazardous waste program by permitting conduct ... that falls below the environmental protections mandated by federal law,” an outcome “contrary to the General Assembly’s express goal and direction to the Department.” Ct. Op. 1187. Even assuming this is true, it is not the job of the judiciary to ensure that Colorado’s program is “consistent with” and “equivalent to” the federal program, as required by federal law. 42 U.S.C. § 6926(b). It is the job of the EPA and, to a lesser extent, the Department, to ensure that the state program is equivalent to the federal scheme. If, in order to be consistent with federal regulations governing CRTs and other electronic devices, it is necessary to limit the resale and reuse of those devices to uses for their “original intended purpose,” then the Department is well within its authority to amend Part 273.2(f)(3) to say that. Absent such an amendment pursuant to the prescribed administrative procedures, I would not “read language into the [regulation] that is not there,” even given a general legislative intent to maintain federal approval. Disher, 224 P.3d at 256.
Briefly, I note why I also disagree with the court’s conclusion that the Waste Instruction satisfied constitutional due process. The court reasons that Defendants had sufficient fair notice because (1) the Waste Instruction was a foreseeable judicial interpretation of Part 273.2(f)(3), (2) Defendants were members of a specialized and technical field, and (3) evidence suggests that Defendants had actual notice of the Department’s Guidance Document. I am not persuaded.
In my view, it was not foreseeable that the district court would interpret Part 273.2(f)(3) to include the “original intended purpose” limitation. It seems far-fetched, at best, to think that any court could have divined such a specific requirement given the general legislative purpose of the Colorado Hazardous Waste Management Act and the federal RCRA. And the other two points largely overlook the significance of the Colorado statutes discussed just above — Colo. Rev. Stat. §§ 25-6.5-102(2) & 24-4-103(1). Given those statutes, the issue is whether Defendants had fair notice that criminal liability could hinge entirely on an informal interpretation (which finds no suggestion in the regulation) that lacks the force and effect of law. Regardless of their status as members of a highly regulated field, it could not have been foreseeable to Defendants that a court — in a hazardous waste enforcement proceeding — would give binding effect to an interpretation that, by statute, lacks the authority to bind.
The court’s approach today incentivizes state regulatory agencies to bypass the formal rule-making process in favor of the more expedient informal interpretations. This is not an incentive I would provide, given the stakes of criminal enforcement actions.
B. Obstruction of Justice
Though the court affirms Mr. Richter’s obstruction of justice conviction, I would also reverse that conviction for two reasons: (1) the erroneous Waste Instruction tainted the jury’s verdict, and (2) there was insufficient evidence to support the government’s alternate theories of obstruction.
As the court notes, the government’s obstruction case turned almost exclusively on the testimony of EPA inspector Eric *1205Johnson. Mr. Johnson testified that he orally requested Mr. Richter turn over “bills of lading and shipping records, any documents related to shipping CRTs from Executive,” 10 R. 1623-24, and that Mr. Richter failed to comply with this request by turning over only a few bills of lading. The government’s theory of the case was that Mr. Richter failed to produce a substantial number of relevant, and requested, documents pertaining to the shipment of CRTs.
Mr. Richter claims he understood Mr. Johnson’s request as one for documents pertaining only to “CRT waste,” not CRTs “in general.” Richter Br. 24-25. Mr. Richter testified that (a) Mr. Johnson requested only “[ejxport waste CRT shipping documents,” 10 R.2062, (b) Mr. Johnson never followed up on the request after Mr. Richter provided initial documentation, id. at 2063, and (c) in his mind, he had complied with the request, id. at 2062. In essence, Mr. Richter argues that Mr. Johnson requested only documents pertaining to “waste” — and because Mr. Richter did not believe that the CRTs exported by Executive fit the regulatory definition of “waste,” he did not believe records pertaining to shipments of reusable CRTs were within the scope of Mr. Johnson’s request.
As discussed above, I conclude that Waste Instruction was improper. Relatedly, I would conclude that the Waste Instruction tainted the jury’s verdict with respect to Mr. Richter’s obstruction conviction. The government’s entire case was predicated on the theory that all CRTs shipped by Executive — broken or unbroken, reusable or non-reusable — constituted regulated “waste.” Given an erroneous definition of “waste,” the jury was likely to conclude that, by failing to turn over any documents related to the shipment of CRTs, Mr. Richter knowingly and intentionally obstructed the EPA’s investigation into violations of hazardous waste laws. As the district court noted, this was an EPA compliance investigation, one which involved “reviewing the paperwork required for hazardous waste management compliance.” 3 R. 674. Because I do not think that the jury could fairly evaluate the charges in this case with a flawed “waste” instruction, I would reverse.
As to the government’s alternate theories of obstruction, I cannot agree with the court that there was “overwhelming evidence that Mr. Richter obstructed justice by altering the GATU invoice and then shredding the original document.” Ct. Op. 1200. As I read the record, the government’s evidence in support of these alternate theories is not enough to give rise to a reasonable inference that Mr. Richter shredded or altered the GATU invoice. For instance, the only evidence cited by the government to establish'that invoices had been altered is the testimony of Executive employee Jessica Goetzfried. Aplee. Br. 54. But Ms. Goetzfried testified only that a customer invoice “appear[ed] to be manipulated,” after the prosecutor pointed to a sequencing irregularity. 10 R. 992. She further testified that she did not alter the invoice and specifically noted that at least four other people had access to Executive’s records, one of whom was Mr. Richter: Id. at 989. She did not testify that Mr. Richter altered the invoice. The government’s evidence suggesting Mr. Richter shredded relevant documents to impede a government investigation is similarly lacking.
Considering the severity of the instructional error (and resulting spillover prejudice) and the lack of evidence to support *1206any of the government’s alternate theories, I would reverse and remand for a new trial.