It seems to me that no matter how thorough your warnings are, there will always be someone foolish enough to get themselves hurt in a way you couldn't have expected. Is there a line somewhere at which any injuries are the user's fault, not the company's even without an explicit warning?
There is no bright, highlighted line, but the test is generally what a reasonable person would do or expect. Not a total moron.
Let's take an example of using spray-on adhesive instead of hairspray. Would a reasonable person pour wood glue into their hair? Well, Hair gel is technically a very weak glue. But would you pour a glue that is (let'S take Gorilla Glue as a typical example) labeled as skin irritant, don't get in contact with eyes and skin onto your hair, or is it a misuse of a product the producer could not have expected?
2.1. Classification of the hazardous chemical Classification according to the model Work Health and Safety Regulations (WHS Regulations)
Flammable aerosols, Category 1 H222
Gases under pressure : Liquefied gas H280
Skin corrosion/irritation, Category 2 H315
Serious eye damage/eye irritation, Category 2A H319
Specific target organ toxicity — Single exposure, Category 3, Narcosis H336
And that is not even the crux: reading the chemical composition and MSDS, that stuff is laden with solvents while its glue-power is what one would expect from superglue. Is it foreseeable that a reasonable person puts superglue in their hair, in any shape or form? Is it even advertised as a possible hair-product?
While you can sue for anything in the US, being stupid and (in our example) dousing your hair in a product advertised as extra-strong spray-on superglue is far from what any reasonable person would do. And in this case, Devin J. Stone and Steve Lehto agree that there are no grounds to sue, product liability does generally not cover gluing your hair to your head.
To win a negligence claim, the plaintiff needs to prove that the defendant:
- had a duty to the plaintiff,
- breached that duty by failing to conform to the required standard of conduct (generally the standard of a reasonable person),
- the plaintiff must have suffered actual harm,
- the negligent conduct was, in law, the cause of that harm, and
- that harm was foreseeable.
If they fail to prove any one of the limbs, the claim fails entirely.
No 1. is trivially proven - a manufacturer owes a duty of care to any potential user of their product. Similarly, nos 3 & 4 seem self-evident.
Should the manufacturer have foreseen the harm that was done?
Should it have occurred to the manufacturer that their glue sold in hardware stores or the hardware section of supermarkets would be used as hairspray?
If the answer is no, they are not liable. If the answer is yes, then we need to look at ...
Standard of Care
Determining the required standard of care is dependant on the circumstances of the particular case:
... it must be observed that in all cases the amount of care which a prudent man will take must vary infinitely according to circumstances. No prudent man in carrying a lighted candle through a powder magazine would fail to take more than if he was going through a damp cellar. The amount of care will be proportionate to the degree of risk run, and to the magnitude of the mischief that may be occasioned.
Mackintosh v Macintosh (1864) 2 Macph (Ct of Sess) 1357 at p 1362.
Or, if the judge were working today, he (because it was certainly a he in 1864) would say "its a risk management problem". That is, the care the defendant needs to take depends on the likelihood and the consequences of the bad outcome for the plaintiff when considered with foresight rather than hindsight.
Because this is a matter of fact and not law, the required standard of care is what the community (as represented by the jury/judge) at the time considers is appropriate.
If there are legal obligations and social norms then these can inform the standard but they are not definitive. So, if the glue manufacture did not comply with all the required or expected packaging and warnings, this can show that they failed to meet the standard. However, compliance with such obligations does not show that they necessarily met the standard - perhaps the obligations are now out of step with community expectations.
Glue is an inherently hazardous substance. However, goods and activities cannot be prohibited simply because of that because society needs to, for example, stick things together, in order to function.
Given that, the manufacture should consider the inherent properties of the product in use and misuse and mitigate the risks as far as reasonably possible.
Glue has to come out of the tube and be applied by people in order to function as glue so providing it in an unopenable container is not going to be possible (lest that seem unreasonable there are plenty of products which have either inaccessible or non-user accessible parts - it takes a lot of effort to touch the electrically live parts of a computer, for example). So the manufacture should consider things like child-proof caps, simple instructions for use (possibly in multiple languages), clear and unambiguous warnings (possibly using internationally recognised pictograms), PPE recommendations, and safety data sheets. These work in concert - its more reasonable to assume that someone old enough to get the childproof cap off is likely to be functionally literate.
So the jury/judge will look at what was done and ask: is this what a reasonable manufacturer should have done or is there something else the should have done but didn't?
The "line" is a label. For this specific example, "Bonds: Wood, Stone, Metal, Ceramic, Foam, Glass and More. WARNING: Eye and Skin Irritant"
That's on the front of the bottle. On the folded label on the back of the bottle are more warnings about proper use and how to remove from skin should you get it on you.
If you've clearly stated the product's purpose, described potential harm that may be caused by using it properly and then stated other harm that could be caused by unauthorized uses, I think you've drawn a very clear line of how to use the product and any other uses and harms that result are the responsibility of the user.
Jury emotion and the ambiguous principle of "equity" makes this question impossible to answer.
Trish and Dale both gave good answers, but in practice if you go looking for a line you won't find one.
Juries don't like to see sympathetic plaintiffs who have experienced significant costs. Given half a chance by a judge, they will want to take some action to mitigate those costs...and the action available to them is to transfer some or all of those costs to a party they see as better suited to bear them: a large company, or their insurer. And as soon as that happens, in any jurisdiction including those notoriously friendly to plaintiffs, you have an existing precedent that others can imitate.