A 46-year-old monk in the Bronx, New York was in his unventilated monastery basement at one AM December 11 when he tipped over a five-gallon bucket of sodium cyanide metal cleaning solution. He was investigating a peculiar smell coming from the basement. His mother called the fire department, who found him not breathing and with no pulse. They restored his breathing and pulse but he did not regain consciousness and died after several days in a coma. The hazardous materials response team (HAZMAT) that responded to the call estimated the hydrogen cyanide (hydrocyanic acid) levels in the basement were 200 ppm (parts per million) or four times the level that is an immediate threat to life.
The team removed over 100 pounds of sodium cyanide from the basement. There was electroplating and etching equipment in the basement, but they were no longer in use. Any cyanide solution can produce the deadly hydrogen cyanide gas when exposed to acid. In addition to the acute effects of hydrogen cyanide gas, chronic (long-term) effects exist and may have contributed to this fatality. There is evidence of reduced brain function, brain lesions, and Parkinson-like symptoms from chronic low level exposure to hydrogen cyanide, symptoms that all result from reduced oxygen supply to the brain.
Cyanide Substitutes There is no reason to use cyanide for cleaning jewelry or other metals since alternatives do exist. Either acid pickling solutions or Sparex can do the same job. They may not be as fast but are not as deadly, although they still require precautions. (With strong acids, precautions include personal protective equipment such as safety glasses with side guards or goggles (no contact lenses), acid-resistant gloves, and access to an eye wash station and a safety shower.) We have been investigating alternatives to cyanide-based products for electroplating or electroforming of gold and silver. The benefits of cyanide-free processes are twofold. First, there is not the immediate threat to life as described above. Second, the only EPA-approved disposal of cyanide waste is incineration. The proper waste disposal of cyanide generated from processes make them prohibitively expensive. Stored cyanide salts can also be a potential hazard if heated or inadvertently exposed to acid. Jewelry makers and metal workers should not use any cyanide-based processes.
The electroplating industry has alternatives for gold and silver electroplating. Jewelry makers need to switch over to these methods. One of the practical alternatives to cyanide-based methods for silver electroplating uses a silver succinimide, which was developed and marketed by Technic Inc. in Providence, RI (its trade name is Silver Cy-less).
For gold electroplating, industry is using a methodology that is based on gold sulfites. One product line of interest is the Techni Gold plating system from Technic Inc. If treated with acid or heated, sulfur dioxide will be released, but this is much less toxic than hydrogen cyanide. Certain products advertised as "cyanide-free" do not contain free sodium cyanide but contain potassium cyanoaurate. Exposure to acid or heating will liberate the deadly hydrogen cyanide. The only way be certain about a product is to get the Material Safety Data Sheets (MSDS). The reactivity section is particularly telling for cyanide-based products because of the warnings about exposure to acid or heat and the release of hydrogen cyanide.
In conclusion, there are possible alternatives to cyanide-based processes for electroplating gold and silver. There are also adequate existing methods to replace sodium cyanide for metal and jewelry cleaning. These alternatives would prevent needless deaths such as the one reported above. We would appreciate feedback from artists on their experience using the cyanide-free methods.