Division 42Production of chlorine gas and sodium hydroxide (caustic soda) solution

### Division 42—Production of chlorine gas and sodium hydroxide (caustic soda) solution 342 (1) The production of chlorine gas and sodium hydroxide solution (caustic soda solution (NaOH(aq))) is the chemical transformation of sodium chloride solution (NaCl(aq)) brine to chlorine (Cl2(1,g)) and sodium hydroxide solution (caustic soda solution (NaOH(aq))) that has a concentration of sodium hydroxide (NaOH) of at least 14%. (2) The production of chlorine gas and sodium hydroxide solution (caustic soda solution (NaOH(aq))) is specified as an emissions‑intensive trade‑exposed activity. (3) The production of chlorine gas and sodium hydroxide solution (caustic soda solution (NaOH(aq))) is a highly emissions‑intensive activity. > Note: See Part 4. (4) The basis for the issue of free carbon units for the production of chlorine gas and sodium hydroxide solution (caustic soda solution (NaOH(aq))) is by a tonne of 100% equivalent sodium hydroxide (caustic soda (NaOH)) on a dry weight basis that: (a) is not recycled back into the emissions‑intensive trade‑exposed activity (such as a stream of sodium hydroxide solution (caustic soda solution NaOH(aq)) recycled back into the chemical treatment step); and (b) is contained within the sodium hydroxide solution produced by carrying on the emissions‑intensive trade‑exposed activity.