Complex sentence: On the night of September 4--5,1934, as the ground crews pumped hydrogen into the silk bag, an unexpected static spark caused by friction of unfolding silk ignited the balloon; there were no fatalities on the ground but the project was shelved indefinitely.
Split into simpler sentences: On the night of September 4--5,1934, as the ground crews pumped hydrogen into the silk bag, an unexpected static spark caused by friction of unfolding silk ignited the balloon. There were no fatalities on the ground but the project was shelved indefinitely.