baɪ ðɪ ˈɛnd ʌvðə nˈaɪntiːnhˈʌndɹɪd fˈɪfti z, lˈiːɡəl pɹˈɑːdʌkt lˌaɪəbˈɪlᵻɾi hɐdbɪn ɪstˈæblɪʃt ɪnwˌɪtʃ ɐn ɐɡɹˈiːvd pˈɑːɹɾi nˈiːd ˈoʊnli pɹˈuːv ˈɪndʒɚɹi baɪ jˈuːs əvə pɹˈɑːdʌkt, ɹˈæðɚ ðɐn bˈɛɹɪŋ ðə bˈɜːdən ʌv pɹˈuːf ʌv kˈɔːɹpɚɹət nˈɛɡlɪdʒəns.
By the end of the 1950s, legal product liability had been established in which an aggrieved party need only prove injury by use of a product, rather than bearing the burden of proof of corporate negligence.