(S (S (S (BASENP (JJ Much) (NN controversy)) (VP (VBD was) (VP (VBN caused) (PP (IN by) (NP (BASENP (DT the) (NN suggestion)) (SBAR (S (BASENP (PRP it)) (VP (MD may) (VP (VB be) (VP (VBN used))))))))))) (COMMA ,) (SBAR (IN since) (S (BASENP (JJ international) (NNS regulations)) (VP (VBP limit) (NP (NP (BASENP (DT the) (NN use)) (PP (IN of) (NP (BASENP (NNS materials)) (VP (VBN intended) (PP (IN for) (BASENP (NN safety) (NNS investigations))))))) (PP (IN as) (NP (NN evidence) (SBAR (S (VP (TO to) (VP (VP (VB prove) (BASENP (NN liability))) (PP (IN in) (BASENP (ADJP (JJ criminal) (CC or) (JJ civil)) (NNS cases)))))))))))))) (PERIOD .))