(S (S (BASENP (DT The) (NN blast)) (VP (VP (VBD happened) (PP (IN at) (BASENP (NN 7:18) (NN PM)))) (COMMA ,) (PP (IN around) (NP (BASENP (DT the) (NN time)) (SBAR (S (BASENP (NNS workers)) (VP (VBP change) (BASENP (NNS shifts))))))))) (PERIOD .))