How South Dakota's Slight vs. Gross Negligence Rule Impacts Product Liability Lawsuits

South Dakota is the only state in the United States that governs negligence claims through a statutory 'slight versus gross' comparative fault framework rather than a fixed 50% or 51% mathematical cutoff. When an everyday workshop tool or household appliance malfunctions-such as a table saw with a jamming blade guard, a lithium-ion cordless drill battery that explodes on the charger, or a countertop pressure cooker whose steam-release lock fails-corporate defense attorneys immediately look for any mistake made by the consumer to block financial recovery under S.D. Codified Laws § 20-9-2.

How South Dakota courts apply user fault depends heavily on whether your lawsuit is pleaded under negligence or strict tort liability, and whether your handling of the tool or appliance crossed the line from minor carelessness into unforeseeable product misuse. Below is a detailed guide to how South Dakota juries weigh consumer conduct against manufacturer defects.

Understanding S.D. Codified Laws § 20-9-2 in Defective Tool and Appliance Claims

In a negligence-based product liability claim-where you allege the manufacturer failed to exercise reasonable care in designing, assembling, or testing an appliance or power tool-S.D. Codified Laws § 20-9-2 controls how shared fault affects your payout. The statute provides that a plaintiff's contributory negligence does not bar recovery only when the plaintiff's contributory negligence was 'slight' in comparison with the negligence of the defendant.

Unlike neighboring states where a jury simply checks whether a plaintiff is 50% or less at fault, South Dakota law forbids using an arbitrary percentage threshold to define 'slight.' As the court established in Wood v. City of Crooks, 559 N.W.2d 558 (SD Supreme Court 1997), whether a plaintiff's negligence is slight is not measured against a hypothetical reasonable person in isolation; instead, it is a direct, side-by-side comparison against the severity of the defendant's conduct in that specific incident. If the manufacturer committed egregious safety shortcuts-such as knowingly using brittle, sub-grade aluminum in a heavy-duty extension ladder-a user's minor lapse in attention may be deemed 'slight' by comparison, allowing recovery with a proportional reduction in damages.

However, South Dakota law treats strict tort liability differently from negligence. In the landmark industrial band saw case Smith v. Smith, 278 N.W.2d 155 (SD Supreme Court 1979), the court held that in a strict liability action, ordinary contributory negligence-such as a worker's failure to discover a hidden defect in a power saw or guard against its possibility-is not a defense at all. Instead, a manufacturer facing a strict liability claim can only defeat recovery by proving unforeseeable product misuse, post-sale alteration, or voluntary assumption of a known risk.

What is Considered Product Misuse?

When a consumer is injured by a power tool, farm implement, or domestic appliance, manufacturers routinely invoke S.D. Codified Laws § 20-9-10 and the misuse doctrine. Under S.D. Codified Laws § 20-9-10, no manufacturer or seller of a product may be held liable for damages sustained by reason of an alteration or modification of the product by the user or a third party made after the initial sale, unless the alteration was foreseeable or directed by the manufacturer.

South Dakota courts draw a sharp legal line between foreseeable imperfect use and unforeseeable product misuse or modification:

• Actionable Product Misuse / Alteration (Bars Recovery): Unbolting and removing the anti-kickback pawls and riving knife from a cabinet table saw, bypassing the thermal automatic shutoff switch on a commercial space heater with copper jumper wire, or using a household immersion blender to mix volatile industrial solvents.
• Foreseeable Use (Does Not Bar Strict Liability): Standing on an aluminum step ladder that buckles under a normal load, as examined in Klug v. Keller Industries, Inc., 328 N.W.2d 847 (SD Supreme Court 1982), or operating an industrial band saw in its factory configuration where an inadequately designed guard fails to protect the operator, as in Smith v. Smith, 278 N.W.2d 155 (SD Supreme Court 1979).

Failure to Follow Instructions vs. Defective Design

A frequent battleground in South Dakota courtrooms occurs when an appliance manufacturer buries a safety disclaimer on page 40 of an owner's manual and blames the injured consumer for failing to read or follow it. Under South Dakota product liability standards, a manufacturer cannot use fine-print instructions as a substitute for safe engineering.

As analyzed in Burley v. Kytec Innovative Sports Equipment, Inc., 737 N.W.2d 397 (SD Supreme Court 2007), manufacturers have a distinct duty to design reasonably safe equipment and provide conspicuous warnings regarding hidden hazards. Under S.D. Codified Laws § 20-9-10.1, juries may evaluate whether the product's design, testing, and warning labels conformed to the prevailing 'state of the art' when first sold. If an electric pressure cooker is engineered with a faulty lid-locking pin that allows the user to twist open the lid while scalding steam is still pressurized inside, the manufacturer's failure to incorporate a standard $2 mechanical pressure interlock is overwhelming evidence of a defective design. Even on a negligence count under S.D. Codified Laws § 20-9-2, a consumer's failure to time a 20-minute natural cool-down period mentioned in the manual is typically viewed as 'slight' when weighed against the manufacturer's 'gross' failure to install an industry-standard safety lock.

How Juries Apportion Fault in SD Courts

When a product liability lawsuit reaches a jury in the Minnehaha County Circuit Court, Second Judicial Circuit, Sioux Falls, the Pennington County Circuit Court, Seventh Judicial Circuit, Rapid City, or the Brookings County Circuit Court, Third Judicial Circuit, Brookings, the judge instructs the jurors to evaluate fault through two distinct steps on negligence counts:

1. Step 1 - The Slight vs. Gross Threshold: If the jury finds both the tool manufacturer and the injured user were negligent, the jury must first compare the two directly. Was the plaintiff's contributory negligence 'slight' (small in amount and of little importance) compared to the manufacturer's negligence? If the jury answers 'No,' the plaintiff recovers $0 on the negligence claim.
2. Step 2 - Proportional Mitigation of Damages: If the jury answers 'Yes,' the plaintiff wins, and the jury reduces the total damages award in direct proportion to the amount of contributory fault attributable to the plaintiff under S.D. Codified Laws § 20-9-2.

Step-by-Step Process for Pursuing a Defective Tool or Appliance Claim in South Dakota

Whether your injury occurred in a workshop in Rapid City, a farmstead near Aberdeen, or a home in Sioux Falls, building a claim that survives defense attacks under S.D. Codified Laws § 20-9-2 and S.D. Codified Laws § 20-9-10 requires immediate action.

Step 1: Secure the Unaltered Tool, Appliance, and Instruction Manual

Unplug the appliance or remove the battery pack immediately and lock the entire item-including detached guards, blades, cords, and original packaging-in a safe place. Never disassemble or test the tool yourself, as defense engineers will claim your post-accident tinkering constitutes product alteration under S.D. Codified Laws § 20-9-10.

Step 2: Retain a Mechanical or Electrical Engineering Expert

To prove the manufacturer's conduct was gross and that the product violated industry safety standards (such as UL or ANSI standards) under S.D. Codified Laws § 20-9-10.1, your attorney will arrange a formal protocol inspection with a forensic engineer. The expert documents how an inexpensive alternative design would have prevented the injury.

Step 3: Plead Both Strict Liability and Negligence Counts

Draft the complaint to include both Strict Tort Liability (under Engberg v. Ford Motor Co., 205 N.W.2d 104 (SD Supreme Court 1973)) and Negligent Design/Failure to Warn. Pleading strict liability protects your claim from being reduced for ordinary carelessness under Smith v. Smith, 278 N.W.2d 155 (SD Supreme Court 1979), while the negligence count allows you to highlight the manufacturer's reckless corporate shortcuts before the jury.

Step 4: File in South Dakota Circuit Court and Serve the Manufacturer

Submit your Complaint, Form UJS-232, South Dakota, Unified Judicial System, Case Filing Statement, and a Summons pursuant to S.D. Codified Laws § 15-6-4(a) in the appropriate Circuit Court, or in the U.S. District Court for the District of South Dakota, Sioux Falls if diversity jurisdiction applies. Complete formal service of the summons on the manufacturer's registered agent through the South Dakota Secretary of State, Pierre within the 3-year window mandated by S.D. Codified Laws § 15-2-12.2 and S.D. Codified Laws § 15-2-30.

Step 5: Navigate Discovery, Subpoenas, and Jury Instructions

Use a civil subpoena issued pursuant to S.D. Codified Laws § 15-6-45 and federal discovery requests to compel the manufacturer to turn over internal quality-control test failures and prior consumer injury reports. You can also check recall records or report the dangerous appliance to the South Dakota Office of the Attorney General, Consumer Protection Division, Pierre.

How Much Does It Cost in South Dakota?

• Circuit Court Filing Fee: $72.00 in any South Dakota Circuit Court, which includes the base civil fee under S.D. Codified Laws § 16-2-29, the court automation fee per S.D. Codified Laws § 16-2-39, and the law library fee (waivable for low-income residents via Form UJS-022, South Dakota, Unified Judicial System, Motion, Affidavit, and Order to Waive Filing Fee & Service of Process Fee), or $405 in the U.S. District Court for the District of South Dakota, Rapid City.
• Forensic Engineering & Lab Testing: Non-destructive CT scanning, metallurgical analysis, and electrical testing of a defective tool or appliance typically cost between $4,000 and $12,000.
• Contingency Lawyer Fees: Product defect attorneys in South Dakota generally advance all litigation and expert costs and charge 33.3% to 40% of the final recovery (plus South Dakota state and municipal sales tax on legal fees), meaning you pay no upfront attorney fees if your claim does not succeed.

How Long Does the Process Take?

Resolving a contested tool or appliance defect claim in South Dakota generally takes 12 to 24 months. After the manufacturer is served, it has 30 days to answer in state court. Joint engineering inspections and depositions of corporate design engineers typically take 8 to 14 months. Because defense lawyers routinely file summary judgment motions arguing that the consumer's conduct was 'more than slight' under S.D. Codified Laws § 20-9-2, hiring an experienced local trial lawyer from our directory of South Dakota attorneys is one of the most effective ways to protect your claim.

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