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Manufacturing
7 min read
Areas of Expertise :
Human Factors, Mechanical Engineering, Labels And Warnings, Product Defect, Product Liability
Published Date:
Last Modified Date:
Jurisdiction:
Federal. Seventh Circuit
Johnson v. Ridge Tool Manufacturing Company, Inc. involved injuries Paul Johnson suffered while operating a RIDGID K-6200 drain-cleaning machine at Northwestern Memorial Delnor Hospital, as the facility was identified in the district court opinion. Johnson brought negligence, product-liability, and failure-to-warn claims against Ridge Tool Company, which the district court noted had been incorrectly identified in the case caption as Ridge Tool Manufacturing Company, Inc.
Johnson alleged that the machine lacked adequate guarding around its rotating cable and that its warnings and safety instructions did not adequately address the risk of injury. His case relied on mechanical engineering testimony concerning a proposed alternative guard and Human Factors testimony addressing the operator’s manual, personal protective equipment, safety controls, and user interaction with the machine.
The U.S. District Court for the Northern District of Illinois excluded both experts’ opinions under Federal Rule of Evidence 702 and granted summary judgment to Ridge Tool. Johnson appealed, and the Seventh Circuit affirmed the judgment on August 7, 2026.
Paul Johnson was operating a RIDGID K-6200 drain-cleaning machine at Northwestern Memorial Delnor Hospital when the rotating cable caught his right hand and glove. His employer had supplied the glove, which Johnson later described as “a little large.”
The incident injured his right hand, arm, and shoulder. Johnson had read the warning label on the machine but had not read the operator’s manual before using it.
Johnson filed suit in Illinois state court, asserting negligence, product-liability, and failure-to-warn claims. Ridge Tool removed the action to the U.S. District Court for the Northern District of Illinois under diversity jurisdiction, where it proceeded as Case No. 1:21-cv-01939.
Johnson claimed that the K-6200 should have included a fixed guard over the exposed rotating cable. He also challenged the warnings provided with the machine and Ridge Tool’s use of personal protective equipment as part of its safety measures.
During discovery, Johnson disclosed mechanical engineer Chad Jones and Human Factors professional Cynthia Rando as expert witnesses.
Jones proposed a fixed coil-spring guard intended to limit an operator’s exposure to the rotating cable. Rando examined the operator’s manual, safety controls, personal protective equipment, and the one-size glove supplied with the K-6200. Ridge Tool moved to exclude both experts’ opinions under Federal Rule of Evidence 702.
U.S. District Judge LaShonda A. Hunt excluded the opinions offered by Jones and Rando.
The court concluded that Jones had not sufficiently supported his proposed guard through testing, calculations, modeling, compatibility analysis, cost analysis, or an evaluation of possible safety tradeoffs.
Rando’s criticism of the operator’s manual could not establish causation because Johnson had not read the manual before the accident. The court also found that she did not offer a specific opinion concerning the adequacy of the warning label Johnson had read or draft and test a specific alternative warning.
In the same memorandum opinion, the district court granted summary judgment to Ridge Tool.
After Jones’s testimony was excluded, Johnson lacked the technical evidence needed to support his proposed alternative design. His failure-to-warn claim also failed because the remaining evidence did not establish that the on-product warning was inadequate or that different warning language would have prevented the injury.
The claims were resolved without a jury trial.
Johnson appealed to the U.S. Court of Appeals for the Seventh Circuit, where the case was docketed as No. 25-2604.
He challenged the exclusion of his experts and the district court’s entry of summary judgment. The appeal addressed the methods used by the mechanical engineering and Human Factors experts and whether Johnson had enough remaining evidence to proceed with his product-liability claims. Briefing continued through late 2025.
Chief Judge Michael B. Brennan and Circuit Judges Frank H. Easterbrook and Rebecca Taibleson heard oral argument.
The parties addressed the district court’s Rule 702 analysis of the mechanical engineering and Human Factors opinions. They also argued over the evidence supporting Johnson’s design-defect and failure-to-warn theories. The panel took the case under advisement after oral argument.
The Seventh Circuit affirmed the district court’s judgment.
It agreed that Jones had not provided sufficient analysis showing that his proposed guard would be feasible and safer when used with the K-6200. The court also upheld the exclusion of Rando’s opinions because much of her analysis concerned a manual Johnson had not read, and she did not offer a specific opinion concerning the adequacy of the warning label or provide a sufficiently developed and tested alternative warning.
The district court’s summary judgment for Ridge Tool remained in place.
Court:
United States Court of Appeals for the Seventh Circuit
Case Name:
Johnson v. Ridge Tool Manufacturing Company, Inc.
Paul Johnson was injured when his glove and hand became caught in the rotating cable of a RIDGID K-6200 drain-cleaning machine.
The case focused on whether the machine required additional guarding and whether its warnings adequately addressed the risk of entanglement.
The district court excluded Johnson’s mechanical engineering and Human Factors experts under Rule 702.
Without the excluded expert testimony, Johnson lacked sufficient evidence to support his design-defect and failure-to-warn claims.
The Seventh Circuit affirmed summary judgment for Ridge Tool in August 2026.
Machine Safety
Machine Guarding
Product Safety
Safety Warnings
Design Defect
Protective Equipment
Rotating Equipment
Johnson v. Ridge Tool Manufacturing Company, Inc. involved injuries Paul Johnson suffered while operating a RIDGID K-6200 drain-cleaning machine at Northwestern Memorial Delnor Hospital, as the facility was identified in the district court opinion. Johnson brought negligence, product-liability, and failure-to-warn claims against Ridge Tool Company, which the district court noted had been incorrectly identified in the case caption as Ridge Tool Manufacturing Company, Inc.
Johnson alleged that the machine lacked adequate guarding around its rotating cable and that its warnings and safety instructions did not adequately address the risk of injury. His case relied on mechanical engineering testimony concerning a proposed alternative guard and Human Factors testimony addressing the operator’s manual, personal protective equipment, safety controls, and user interaction with the machine.
The U.S. District Court for the Northern District of Illinois excluded both experts’ opinions under Federal Rule of Evidence 702 and granted summary judgment to Ridge Tool. Johnson appealed, and the Seventh Circuit affirmed the judgment on August 7, 2026.
Paul Johnson was operating a RIDGID K-6200 drain-cleaning machine at Northwestern Memorial Delnor Hospital when the rotating cable caught his right hand and glove. His employer had supplied the glove, which Johnson later described as “a little large.”
The incident injured his right hand, arm, and shoulder. Johnson had read the warning label on the machine but had not read the operator’s manual before using it.
Johnson filed suit in Illinois state court, asserting negligence, product-liability, and failure-to-warn claims. Ridge Tool removed the action to the U.S. District Court for the Northern District of Illinois under diversity jurisdiction, where it proceeded as Case No. 1:21-cv-01939.
Johnson claimed that the K-6200 should have included a fixed guard over the exposed rotating cable. He also challenged the warnings provided with the machine and Ridge Tool’s use of personal protective equipment as part of its safety measures.
During discovery, Johnson disclosed mechanical engineer Chad Jones and Human Factors professional Cynthia Rando as expert witnesses.
Jones proposed a fixed coil-spring guard intended to limit an operator’s exposure to the rotating cable. Rando examined the operator’s manual, safety controls, personal protective equipment, and the one-size glove supplied with the K-6200. Ridge Tool moved to exclude both experts’ opinions under Federal Rule of Evidence 702.
U.S. District Judge LaShonda A. Hunt excluded the opinions offered by Jones and Rando.
The court concluded that Jones had not sufficiently supported his proposed guard through testing, calculations, modeling, compatibility analysis, cost analysis, or an evaluation of possible safety tradeoffs.
Rando’s criticism of the operator’s manual could not establish causation because Johnson had not read the manual before the accident. The court also found that she did not offer a specific opinion concerning the adequacy of the warning label Johnson had read or draft and test a specific alternative warning.
In the same memorandum opinion, the district court granted summary judgment to Ridge Tool.
After Jones’s testimony was excluded, Johnson lacked the technical evidence needed to support his proposed alternative design. His failure-to-warn claim also failed because the remaining evidence did not establish that the on-product warning was inadequate or that different warning language would have prevented the injury.
The claims were resolved without a jury trial.
Johnson appealed to the U.S. Court of Appeals for the Seventh Circuit, where the case was docketed as No. 25-2604.
He challenged the exclusion of his experts and the district court’s entry of summary judgment. The appeal addressed the methods used by the mechanical engineering and Human Factors experts and whether Johnson had enough remaining evidence to proceed with his product-liability claims. Briefing continued through late 2025.
Chief Judge Michael B. Brennan and Circuit Judges Frank H. Easterbrook and Rebecca Taibleson heard oral argument.
The parties addressed the district court’s Rule 702 analysis of the mechanical engineering and Human Factors opinions. They also argued over the evidence supporting Johnson’s design-defect and failure-to-warn theories. The panel took the case under advisement after oral argument.
The Seventh Circuit affirmed the district court’s judgment.
It agreed that Jones had not provided sufficient analysis showing that his proposed guard would be feasible and safer when used with the K-6200. The court also upheld the exclusion of Rando’s opinions because much of her analysis concerned a manual Johnson had not read, and she did not offer a specific opinion concerning the adequacy of the warning label or provide a sufficiently developed and tested alternative warning.
The district court’s summary judgment for Ridge Tool remained in place.
Human Factors Expert Witness
Cynthia Rando, a certified Human Factors professional with approximately 20 years of experience, was retained by Johnson. Her report addressed the operator’s manual, safety controls, personal protective equipment, and risks associated with the one-size glove supplied with the K-6200.
Her analysis of the manual faced a causation problem because Johnson had not read it before the accident. The courts also found that she did not offer a specific opinion concerning the adequacy of the warning label affixed to the machine or develop and test a specific alternative warning. Her opinions were excluded under Rule 702.
Mechanical Engineering and Machine Safety Expert Witness
Chad Jones, a mechanical engineer and Certified Machine Safety Expert, evaluated Johnson’s design-defect allegations.
He proposed a fixed coil-spring guard intended to reduce an operator’s contact with the rotating cable. The district court concluded that the proposal was not supported by sufficient testing, calculations, modeling, compatibility analysis, cost analysis, or evaluation of possible safety tradeoffs. His alternative-design opinions were excluded before the court entered summary judgment.
Equipment Operation and Product Safety Expert Witness
Ridge Tool identified John Smyth as a proposed expert concerning operation of the K-6200.
Smyth stated that use of the optional front guide hose was recommended when the machine was positioned more than three feet from the sewer opening and that Johnson was operating within three feet of the opening.
The Warning Label and Operator’s Manual Were Evaluated Separately
The case involved safety information presented in more than one form. Johnson had read the warning label attached to the K-6200 but had not read the operator’s manual before the accident.
That distinction affected the Human Factors analysis. Criticism directed at the manual did not establish that its contents influenced Johnson’s actions before the incident because he had not reviewed it.
The Failure-to-Warn Claim Focused on the Warning Johnson Actually Read
Johnson’s failure-to-warn theory required evidence addressing the adequacy of the on-product warning and whether a different warning would have affected his conduct.
The district court found that Rando did not offer a specific opinion concerning the adequacy of that warning label. She also did not draft and test a specific alternative warning that could be evaluated against the warning Johnson encountered.
The Proposed Guard Required Product-Specific Engineering Analysis
Jones proposed a fixed coil-spring guard intended to reduce exposure to the rotating cable. The court examined whether that design had been sufficiently evaluated for actual use with the K-6200.
The opinion identified missing testing, calculations, modeling, compatibility analysis, cost analysis, and consideration of possible safety tradeoffs. Those deficiencies affected whether the proposed alternative design could support Johnson’s design-defect claim.
Rule 702 Applied Separately to the Engineering and Human Factors Opinions
Federal Rule of Evidence 702 governed the admissibility of both experts’ testimony, but the reliability issues differed.
Jones’s opinions centered on whether his alternative design had been adequately developed and analyzed. Rando’s opinions involved the relationship between the manual, warning label, personal protective equipment, and Johnson’s conduct before the accident.
The Design-Defect and Warning Claims Depended on Different Evidence
Johnson’s design-defect theory focused on the physical configuration of the K-6200 and whether a safer alternative guard could have been used. That theory depended heavily on engineering analysis of feasibility, performance, compatibility, and safety consequences.
The failure-to-warn claim instead focused on the safety information communicated to Johnson. Because he had read the machine warning but not the manual, the evidence concerning those two forms of communication was not treated as interchangeable.
The litigation ended in Ridge Tool’s favor after the district court excluded Johnson’s mechanical engineering and Human Factors opinions and granted summary judgment in August 2025. The Seventh Circuit affirmed on August 7, 2026, leaving the district court’s judgment in place.
What happened in Johnson v. Ridge Tool?
Paul Johnson was injured when his glove and right hand became caught in the rotating cable of a RIDGID K-6200 drain-cleaning machine. He later brought product-liability and failure-to-warn claims alleging problems with the machine’s guarding and safety warnings.
What warnings were at issue in the RIDGID K-6200 case?
The case involved an on-product warning and safety information contained in the K-6200 operator’s manual. Johnson had read the warning label on the machine but had not read the operator’s manual before the accident.
Why did the operator’s manual become an issue in the Human Factors analysis?
Cynthia Rando criticized portions of the operator’s manual, but Johnson had not read the manual before the accident. The court therefore concluded that criticism of the manual could not establish that its contents caused or contributed to his conduct before the injury.
Why was the proposed coil-spring guard rejected as expert evidence?
Johnson’s mechanical engineering expert proposed a fixed coil-spring guard intended to reduce operator exposure to the rotating cable. The courts found that the proposed design lacked sufficient testing and analysis concerning feasibility, safety, compatibility, cost, and possible safety tradeoffs.
What was the final ruling in Johnson v. Ridge Tool?
Ridge Tool prevailed on summary judgment. The Northern District of Illinois entered judgment in its favor in August 2025, and the Seventh Circuit affirmed that judgment on August 7, 2026.
Human Factors Expert Witness
Cynthia Rando, a certified Human Factors professional with approximately 20 years of experience, was retained by Johnson. Her report addressed the operator’s manual, safety controls, personal protective equipment, and risks associated with the one-size glove supplied with the K-6200.
Her analysis of the manual faced a causation problem because Johnson had not read it before the accident. The courts also found that she did not offer a specific opinion concerning the adequacy of the warning label affixed to the machine or develop and test a specific alternative warning. Her opinions were excluded under Rule 702.
Mechanical Engineering and Machine Safety Expert Witness
Chad Jones, a mechanical engineer and Certified Machine Safety Expert, evaluated Johnson’s design-defect allegations.
He proposed a fixed coil-spring guard intended to reduce an operator’s contact with the rotating cable. The district court concluded that the proposal was not supported by sufficient testing, calculations, modeling, compatibility analysis, cost analysis, or evaluation of possible safety tradeoffs. His alternative-design opinions were excluded before the court entered summary judgment.
Equipment Operation and Product Safety Expert Witness
Ridge Tool identified John Smyth as a proposed expert concerning operation of the K-6200.
Smyth stated that use of the optional front guide hose was recommended when the machine was positioned more than three feet from the sewer opening and that Johnson was operating within three feet of the opening.
The Warning Label and Operator’s Manual Were Evaluated Separately
The case involved safety information presented in more than one form. Johnson had read the warning label attached to the K-6200 but had not read the operator’s manual before the accident.
That distinction affected the Human Factors analysis. Criticism directed at the manual did not establish that its contents influenced Johnson’s actions before the incident because he had not reviewed it.
The Failure-to-Warn Claim Focused on the Warning Johnson Actually Read
Johnson’s failure-to-warn theory required evidence addressing the adequacy of the on-product warning and whether a different warning would have affected his conduct.
The district court found that Rando did not offer a specific opinion concerning the adequacy of that warning label. She also did not draft and test a specific alternative warning that could be evaluated against the warning Johnson encountered.
The Proposed Guard Required Product-Specific Engineering Analysis
Jones proposed a fixed coil-spring guard intended to reduce exposure to the rotating cable. The court examined whether that design had been sufficiently evaluated for actual use with the K-6200.
The opinion identified missing testing, calculations, modeling, compatibility analysis, cost analysis, and consideration of possible safety tradeoffs. Those deficiencies affected whether the proposed alternative design could support Johnson’s design-defect claim.
Rule 702 Applied Separately to the Engineering and Human Factors Opinions
Federal Rule of Evidence 702 governed the admissibility of both experts’ testimony, but the reliability issues differed.
Jones’s opinions centered on whether his alternative design had been adequately developed and analyzed. Rando’s opinions involved the relationship between the manual, warning label, personal protective equipment, and Johnson’s conduct before the accident.
The Design-Defect and Warning Claims Depended on Different Evidence
Johnson’s design-defect theory focused on the physical configuration of the K-6200 and whether a safer alternative guard could have been used. That theory depended heavily on engineering analysis of feasibility, performance, compatibility, and safety consequences.
The failure-to-warn claim instead focused on the safety information communicated to Johnson. Because he had read the machine warning but not the manual, the evidence concerning those two forms of communication was not treated as interchangeable.
The litigation ended in Ridge Tool’s favor after the district court excluded Johnson’s mechanical engineering and Human Factors opinions and granted summary judgment in August 2025. The Seventh Circuit affirmed on August 7, 2026, leaving the district court’s judgment in place.
What happened in Johnson v. Ridge Tool?
Paul Johnson was injured when his glove and right hand became caught in the rotating cable of a RIDGID K-6200 drain-cleaning machine. He later brought product-liability and failure-to-warn claims alleging problems with the machine’s guarding and safety warnings.
What warnings were at issue in the RIDGID K-6200 case?
The case involved an on-product warning and safety information contained in the K-6200 operator’s manual. Johnson had read the warning label on the machine but had not read the operator’s manual before the accident.
Why did the operator’s manual become an issue in the Human Factors analysis?
Cynthia Rando criticized portions of the operator’s manual, but Johnson had not read the manual before the accident. The court therefore concluded that criticism of the manual could not establish that its contents caused or contributed to his conduct before the injury.
Why was the proposed coil-spring guard rejected as expert evidence?
Johnson’s mechanical engineering expert proposed a fixed coil-spring guard intended to reduce operator exposure to the rotating cable. The courts found that the proposed design lacked sufficient testing and analysis concerning feasibility, safety, compatibility, cost, and possible safety tradeoffs.
What was the final ruling in Johnson v. Ridge Tool?
Ridge Tool prevailed on summary judgment. The Northern District of Illinois entered judgment in its favor in August 2025, and the Seventh Circuit affirmed that judgment on August 7, 2026.
Machine Safety
Machine Guarding
Product Safety
Safety Warnings
Design Defect
Protective Equipment
Rotating Equipment
Manufacturing
Metallurgy, +4
Manufacturing
Manufacturing, +4
Manufacturing