Youngs syndrome is believed to be a long-term consequence of early childhood mercury poisoning.Mercuric chloride may cause cancer as it has caused increases in several types of tumors in rats and mice, while methyl mercury has caused kidney tumors in male rats. The EPA has classified mercuric chloride and methyl mercury as possible human carcinogens (ATSDR, EPA)

Detection in biological fluids
Mercury may be measured in blood or urine to confirm a diagnosis of poisoning in hospitalized people or to assist in the forensic investigation in a case of fatal over dosage. Some analytical techniques are capable of distinguishing organic from inorganic forms of the metal. The concentrations in both fluids tend to reach high levels early after exposure to inorganic forms, while lower but very persistent levels are observed following exposure to elemental or organic mercury. Chelation therapy can cause a transient elevation of urine mercury levels. History
Neolithic artists using cinnabar show signs of mercury poisoning. Several Chinese emperors and other Chinese nobles are known or suspected to have died or been sickened by mercury poisoning after alchemists administered them "elixirs" to promote health, longevity, or immortality that contained either elemental mercury or (more commonly) cinnabar. Among the most prominent examples:
The first emperor of unified China, Qin Shi Huang, it is reported, died in 210 BC of ingesting mercury pills that were intended to give him eternal life. Emperor Xuānzong of Tang, one of the emperors of the late Tang dynasty of China, was prescribed "cinnabar that had been treated and subdued by fire" to achieve immortality.
Thiomersal
In 1999, the Centers for Disease Control (CDC) and the American Academy of Pediatrics (AAP) asked vaccine makers to remove the organomercury compound thiomersal (spelled "thimerosal" in the US) from vaccines as quickly as possible, and thiomersal has been phased out of US and European vaccines, except for some preparations of influenza vaccine. The CDC and the AAP followed the precautionary principle, which assumes that there is no harm in exercising caution even if it later turns out to be unwarranted, but their 1999 action sparked confusion and controversy that thiomersal was a cause of autism.Since 2000, the thiomersal in child vaccines has been alleged to contribute to autism, and thousands of parents in the United States have pursued legal compensation from a federal fund. A 2004 Institute of Medicine (IOM) committee favored rejecting any causal relationship between thiomersal-containing vaccines and autism. Autism incidence rates increased steadily even after thiomersal was removed from childhood vaccines. Currently there is no accepted scientific evidence that exposure to thiomersal is a factor in causing autism. Dental amalgam toxicity
Dental amalgam is a possible cause of low-level mercury poisoning due to its use in dental fillings. Discussion on the topic includes debates on whether amalgam should be used, with critics arguing that its toxic effects make it unsafe. Cosmetics
Some skin whitening products contain the toxic mercury(II) chloride as the active ingredient. When applied, the chemical readily absorbs through the skin into the bloodstream. The use of mercury in cosmetics is illegal in the United States.