( It ( ( is ( ( formed ( as ( a by-product ) ) ) ( ( ( ( while ( ( ( ( making ( other chemicals ) ) , ) ( in ( the waste ) ) ) ( streams ( of ( ( chloralkali and ) ( wood-preserving plants ) ) ) ) ) ) , ) and ) ( when ( burning ( municipal waste ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (VP (VBN formed) (PP (IN as) (NP (DT a) (NN by-product))) (SBAR (SBAR (IN while) (S (S (VP (VBG making) (NP (JJ other) (NNS chemicals)) (, ,) (PP (IN in) (NP (DT the) (NN waste))))) (VP (VBZ streams) (PP (IN of) (NP (NP (NNS chloralkali)) (CC and) (NP (JJ wood-preserving) (NNS plants))))))) (, ,) (CC and) (SBAR (WHADVP (WRB when)) (S (VP (VBG burning) (NP (JJ municipal) (NN waste)))))))) (. .)))
It is formed as a by-product while making other chemicals, in the waste streams of chloralkali and wood-preserving plants, and when burning municipal waste.
(ROOT (S (NP (NP (DT The) (NN action)) (PP (IN of) (S (VP (VBG burning) (NP (NP (DT a) (NN piece)) (PP (IN of) (NP (NN wood)))))))) (VP (VBZ forms) (NP (DT a) (JJ different) (NN chemical) (NN substance))) (. .)))