In 1840 Charles Henry Hills established a factory at LLam Carw near Amlwch port to make Sulphuric acid via the direct pyritic process. By September 1860 Hills was trying to form an agreement with Evan Evans of the Mona mine to calcine their ores to make sulphuric acid. By 1861 a plant was built which produced 15,000 lbs of 15.5 % sulphuric acid per week. Over the following years the amount of sulpur made from mine ore began to decrease and Hill was forced to import sulphur from as far a way as Spain.  He also imported ground phosphate rock. The phosphate rock was reacted on by sulphuric acid to make range of fertilizers as was described in a 1889 advertisement.:-
" The firm has produced nitro phosphates for the last 36 years, and as a general fertilizer for all kinds of crops, it has given utmost satisfaction. Their bone manure has also proved to be made of the best ingredients and is used by hundreds of farmers. The company's corn and grass manure,...contain more Nitrogen and Ammonia than the NitroPhosphate. The Potato Fertilizer ... contains more essential elements than other products.  The all purpose Phospho Guano is in great demand for Corn and grass."
The last of these materials explains why Guano was being imported from South America to Amlwch Port.
In 1881 Mr Lewis Hughes was listed as manager of the Chemical  and Manure works.
In May 1893 an enormous fire swept through the works. This was caused by one of the hot furnaces cracking and the material inside flowing onto coal. The fire took hold in the roof and 50 roof trusses had to be replaced. Once rebuilt the works seemed to have had a new lease of life under a new manager called Lewis Hughes. In the early months of 1898 additional men were employed to work 24 hours per day. In February alone 6 ships delivered raw material to the port. The works eventually closed in 1910.

Bill head of Henry Hills & Son 1906