"If one or a few of the key suppliers collapse then everything is over with and we're in for a really serious problem," said Cole. Two major suppliers -- Visteon and Metaldyne -- sought bankruptcy protection last week and scores more remain at risk due to low production volumes even if GM gets permission to continue to pay suppliers during its restructuring. The U.S. automotive industry is so highly integrated that the loss of just a few key suppliers could grind production to a halt not only at the Detroit Three but also at the U.S. plants of Japanese and European carmakers.