Trade Secrets

Du Pont v. Christopher: Spying From the Sky as 'Improper Means'

A 1970 Fifth Circuit decision held that aerial photography of a plant under construction was an improper means of acquiring a trade secret, even though the photographers broke no law and breached no confidence.

March 17, 2025
A small aircraft flying low over an industrial chemical plant
Du Pont v. Christopher held that photographing an exposed plant from the air could be misappropriation even where no fence was cut and no promise was broken. Shutterstock
Educational content, not legal advice. This article explains general legal concepts. It does not create an attorney–client relationship. For your specific situation, consult a licensed attorney.

In E.I. du Pont deNemours & Co. v. Christopher, No. 28254, 431 F.2d 1012 (5th Cir. July 20, 1970), the United States Court of Appeals for the Fifth Circuit confronted a deceptively simple question: is it wrongful to learn a competitor’s secret by photographing it from an airplane, when the photographer trespasses on no land, cuts no fence, and breaks no promise? Writing for the panel, Circuit Judge Irving Goldberg answered yes—and in doing so produced one of the most durable statements in American trade-secret law about what makes the acquisition of a secret “improper.” The decision is famous precisely because the defendants did nothing that any other body of law forbade. They flew a plane over Texas and took pictures. The court still held that they could be liable.

At a glance

  • Case: E.I. du Pont deNemours & Co. v. Christopher, No. 28254
  • Court: U.S. Court of Appeals for the Fifth Circuit
  • Author: Circuit Judge Irving L. Goldberg
  • Decided: July 20, 1970
  • Posture: Interlocutory appeal under 28 U.S.C. § 1292(b) from the district court’s denial of the defendants’ motion to dismiss for failure to state a claim
  • Governing law: Texas trade-secret law (diversity jurisdiction), informed by the Restatement (First) of Torts § 757
  • Holding: Aerial photography of a plant under construction, taken to capture an exposed but secret manufacturing process, can constitute discovery of a trade secret by “improper means,” even absent trespass, breach of confidence, or any independently unlawful act
  • Significance: The canonical authority that “improper means” is a freestanding category of misappropriation, not a synonym for illegality or breach of a confidential relationship

On March 19, 1969, Rolfe and Gary Christopher, a father-and-son aerial-photography team, flew over a Du Pont plant under construction in Beaumont, Texas, and took photographs at the direction of an undisclosed third party. The plant was being built to produce methanol by a secret, unpatented process. Du Pont sued, alleging that the photographs captured enough of the plant’s exposed layout to reveal the secret process to a trained observer, and that the Christophers had thereby wrongfully acquired Du Pont’s trade secret. The defendants moved to dismiss, arguing that because they had committed no trespass and breached no confidential relationship, they had done nothing actionable. The district court refused to dismiss and certified the question for interlocutory appeal.

Improper means as its own category

The Christophers’ argument had real force under the conventional framing of trade-secret doctrine. Most misappropriation cases fall into one of two familiar buckets: a defendant breaches a confidential relationship (the departing employee, the licensee who exceeds the license), or a defendant commits some independently wrongful act (breaking and entering, wiretapping, bribery). The Christophers fit neither. They were strangers to Du Pont, owed it no duty of confidence, and—crucially—violated no Texas statute and committed no trespass, because they flew through public, navigable airspace.

The Fifth Circuit refused to treat that gap as dispositive. Drawing on the Restatement (First) of Torts § 757, the court reasoned that liability attaches to anyone who discovers a secret “by improper means,” and that improper means is a category broader than, and independent of, both breach of confidence and breach of some other positive law. The court’s most quoted formulation captures the point: a defendant should not “appropriate a trade secret through deviousness” or by methods “which fall below the generally accepted standards of commercial morality and reasonable conduct.” The touchstone is not whether the conduct was illegal but whether it was a fair way to compete.

The opinion is candid that this standard resists mechanical application. As Judge Goldberg framed it, “improper” will always be a word of many nuances, determined by time, place, and circumstances. That is not a bug but the design: the category exists precisely to reach novel forms of industrial espionage that the legislature and the common law of trespass have not yet caught up with. Aerial photography in 1969 was exactly such a novelty.

Why a roof was not required

The defendants’ fallback was an argument about reasonable precautions. Trade-secret protection has always been conditioned on the owner’s taking reasonable steps to keep the information secret; a holder who leaves a secret in plain view forfeits protection. The Christophers contended that Du Pont’s process was, in effect, in plain view—visible from the sky to anyone who cared to look—and that Du Pont could have prevented the exposure by roofing the unfinished plant.

The court rejected the demand that owners defend against every conceivable mode of surveillance. In its words, courts “need not require the discoverer of a trade secret to guard against the unanticipated, the undetectable, or the unpreventable methods of espionage now available.” To require Du Pont to roof a plant still under construction “to guard its secret would impose an enormous expense to prevent nothing more than a school boy’s trick.” Reasonable precautions, in other words, are measured against foreseeable and preventable intrusions, not against extraordinary and covert ones. A fenced, guarded construction site is reasonably protected even if it is briefly visible from an aircraft, because the owner cannot practically anticipate or defeat aerial reconnaissance.

This is the analytical heart of the decision. It reframes the precautions inquiry away from a strict “if you could have stopped it, you should have” rule toward a proportionality assessment: the law will not force an owner to spend ruinously to defeat espionage that lies outside the ordinary run of competitive behavior. Judge Goldberg tied that conclusion to a broader principle—“our ethos has never given moral sanction to piracy”—signaling that the precautions requirement should not become a charter for clever appropriation.

What the court did not decide

Because Christopher arrived on an interlocutory appeal from a motion to dismiss, the Fifth Circuit decided only that Du Pont had stated a claim. It did not find the Christophers liable, resolve whether the photographs in fact revealed the secret, or address damages. The holding is therefore a ruling about the legal sufficiency of a theory, not a verdict. That posture matters: the case stands for the availability of an improper-means claim on these facts, leaving the factual proof of misappropriation to be developed on remand.

Open questions

Christopher announced a flexible standard and then, by its nature, declined to map its outer boundary. Several questions remain live. First, how far does “commercial morality” extend to conduct that is increasingly routine—drone overflights, satellite imagery, and public-domain data scraping—where the marginal cost of observation has collapsed since 1970? The court excused Du Pont from defending against the “unanticipated”; conduct that was unanticipated then may be entirely foreseeable now, which could shift the precautions calculus against owners. Second, the decision leaves unclear how to treat information that is genuinely observable from a place the observer has every right to be: the line between lawfully perceiving what is exposed and “deviously” appropriating it is easier to state than to draw. Third, because the Uniform Trade Secrets Act and the Defend Trade Secrets Act both codified “improper means” while expressly preserving reverse engineering and independent development as proper, courts must continually police the boundary between aggressive-but-fair intelligence gathering and actionable espionage—a boundary Christopher identified but could not fix.

Implications

  • Improper means is not limited to illegality. A defendant can be liable for acquiring a secret even without committing a trespass, a crime, or a breach of contract, if the method falls below accepted standards of commercial morality.
  • Reasonable precautions are judged by proportionality. Owners need not defend against unanticipated or unpreventable surveillance; a guarded, fenced facility can remain protected even if briefly exposed to extraordinary means of observation.
  • The standard is fact-bound and evolving. Because “improper” depends on time, place, and circumstance, what counts as fair competitive intelligence shifts as technology makes new forms of observation cheap and routine.
  • Codification preserved the concept. Both the UTSA and the DTSA carry forward “improper means” while protecting reverse engineering and independent discovery, so Christopher’s line-drawing remains directly relevant under modern statutes.
  • Plan intelligence-gathering with morality, not just legality, in mind. Counsel advising on competitive intelligence cannot stop at “is it legal?”; the operative question is whether a court would call the method fair.

Frequently asked questions

Did the Christophers break any law by flying over the plant? No. The court accepted that the defendants committed no trespass and violated no statute—they flew through public airspace. The decision’s significance is precisely that liability for trade-secret misappropriation can attach to acquisition by “improper means” even when the conduct is otherwise lawful.

Why wasn’t Du Pont penalized for leaving the process visible from the air? The court held that reasonable precautions are measured against foreseeable and preventable intrusions. Requiring Du Pont to roof a plant still under construction to defeat aerial photography would impose an enormous expense to thwart an extraordinary, hard-to-anticipate method—more than the law demands.

Is reverse engineering treated the same way? No, and that contrast is central. Reverse engineering of a lawfully obtained product and independent development are “proper” means; they are the fair labor the law encourages. Christopher condemns shortcuts that bypass that labor through devious acquisition, a distinction later statutes expressly preserved.

Authorities and sources