Editing Leblanc process (section)

== Pollution issues ==
The Leblanc process plants were quite damaging to the local environment.  The process of generating salt cake from salt and sulfuric acid released [[hydrogen chloride|hydrochloric acid gas]], and because this acid was industrially useless in the early 19th century, it was simply vented into the atmosphere. Also, an insoluble smelly solid waste was produced.  For every 8 tons of soda ash, the process produced 5.5 tons of [[hydrogen chloride]] and 7 tons of calcium sulfide waste. This solid waste (known as galligu) had no economic value, and was piled in heaps and spread on fields near the soda works, where it weathered to release [[hydrogen sulfide]], the toxic gas responsible for the odor of rotten eggs.{{Citation needed|date=January 2021}}

Because of their noxious emissions, Leblanc soda works became targets of lawsuits and legislation.  An 1839 suit against soda works alleged, "the gas from these manufactories is of such a deleterious nature as to blight everything within its influence, and is alike baneful to health and property. The herbage of the fields in their vicinity is scorched, the gardens neither yield fruit nor vegetables; many flourishing trees have lately become rotten naked sticks. Cattle and poultry droop and pine away. It tarnishes the furniture in our houses, and when we are exposed to it, which is of frequent occurrence, we are afflicted with coughs and pains in the head ... all of which we attribute to the Alkali works."<ref name="Council1840">{{cite book|author=Newcastle upon Tyne (England). Town Council|title=Newcastle Council Reports|url=https://books.google.com/books?id=4hZMAQAAMAAJ&pg=RA2-PA19|year=1840|pages=2–}}</ref>

In 1863, the British Parliament passed the [[Alkali Act 1863]], the first of several [[Alkali Act]]s, the first modern [[air pollution]] legislation.  This act allowed that no more than 5% of the hydrochloric acid produced by alkali plants could be vented to the atmosphere.  To comply with the legislation, soda works passed the escaping hydrogen chloride gas up through a tower packed with [[charcoal]], where it was absorbed by water flowing in the other direction.  The chemical works usually dumped the resulting [[hydrochloric acid]] solution into nearby bodies of water, killing [[fish]] and other aquatic life.{{Citation needed|date=January 2021}}

The Leblanc process also meant very unpleasant working conditions for the operators. It originally required careful operation and frequent operator interventions (some involving heavy manual labour) into processes giving off hot noxious chemicals.<ref>Russell. Colin Archibald, Chemistry, society and environment: a new history of the British chemical industry, Royal Society of Chemistry, 2000. {{ISBN|0-85404-599-6}}</ref>
Sometimes, workmen cleaning the reaction products out of the reverberatory furnace wore cloth mouth-and-nose [[gag]]s to keep dust and [[aerosol]]s out of the lungs.<ref>Described, and called a "gag", in a recorded commentary in [[Catalyst (museum)|the Catalyst chemical industry museum]] in Runcorn (Cheshire, England), to keep alkali dust out of workers' lungs in the early years of the [[chemical industry]] in Britain.</ref><ref>{{cite web |work=Dig This! The Newsletter of 3D Archaeological Society |volume=11 |issue=3 |page=7 |date=September 2017 |title=What did our Ancestors do? |url=https://3darchaeology.co.uk/wp-content/uploads/2017/06/Volume-11-Issue-3.pdf |archive-url=https://web.archive.org/web/20190417141629/https://3darchaeology.co.uk/wp-content/uploads/2017/06/Volume-11-Issue-3.pdf |archive-date=2019-04-17 |last=Beeby |first=Ann |access-date=2022-08-11 }}</ref>

This improved somewhat later as processes were more heavily mechanised to improve economics and uniformity of product.{{Citation needed|date=January 2021}}

By the 1880s, methods for converting the hydrochloric acid to [[chlorine]] gas for the manufacture of [[Bleach (chemical)|bleach]]ing powder and for reclaiming the sulfur in the calcium sulfide waste had been discovered, but the Leblanc process remained more wasteful and more polluting than the [[Solvay process]].  The same is true when it is compared with the later electrolytical processes which eventually replaced it for chlorine production.{{Citation needed|date=January 2021}}