Dow Jones Industrial Average opened higher on Monday but retreated and ended slightly lower as strongly lower than expected ISM manufacturing data weighed on production companies. Blue chip index shed 0.07% or 8.70 points and settled at 12,871.39. Manufacturers slipped on worries about the first contraction in three years. General Electric declined 1.7% while Boeing Co and Caterpillar each dropped 1.5%. The ISM manufacturing gauge tumbled from 53.5 in May to 49.7 in June, surpassing even the most pessimistic predictions.