Officials have announced a state of emergency in New Haven, Connecticut after at least 76 people overdosed on a synthetic marijuana alternative.

The harrowing incident is just the latest in a wave of synthetic marijuana overdoses nationwide, in which hundreds of victims have suffered a myriad of side effects, from bleeding out of their eye sockets to delusional thinking and repeated vomiting.

The synthetic drug is known as K2; it looks similar to marijuana and is smoked the same way as cannabis, but can cause deadly side effects due to its unregulated and varying mixture of chemical compounds. Researchers and police believe the recent string of K2 overdoses may have been caused in part by mixing the drug with opioids, fentanyl, or unknown compounds imported from Russia and China.

"It’s really hard to say what causes these big outbreaks, because people don’t really know what they’re getting when they buy K2 spices," said Paul Prather, a principle investigator for the College of Medicine at the University of Arkansas for Medical Services. "These products are made specifically to evade detection, so what may be going on is that we’re seeing the introduction of new compounds into the market that have never been tested on animals or humans."

Police arrested a 37-year-old man believed to be connected to the overdoses at New Haven Green, a city park near Yale University. There were nearly 25 overdoses in a three-hour period at the park on Tuesday, with dozens more continuing throughout the night and into Wednesday. Victims began collapsing in broad daylight and convulsing on the floor, as paramedics rushed to the scene.

It’s not the first time an outbreak of overdoses occurred at "the Green," as locals refer to the city park known for attracting drug users and the homeless. Nearly a dozen victims overdosed at the park on 4 July this year.

City officials warned residents about the dangerous drug after numerous victims were hospitalised with life-threatening conditions, telling locals not to buy K2 at the Green — or anywhere, for that matter.

"Today New Haven was on the front lines of a coast-to-coast struggle to combat the public health menace of illicit distribution and use of what appear to be tainted street drugs," New Haven Mayor Toni Harp said in a statement.

Connecticut Governor Dannel Malloy also echoed that warning, saying in a statement, "The substance behind these overdoses is highly dangerous and must be avoided."

76 people overdose on synthetic marajuana in a single day at a park in Canada

Mr Prather, whose conducted years of studies into K2 and its potentially lethal side effects, described a black market system behind K2 in which street dealers are buying and mixing unknown chemicals themselves.

"It’s mostly nefarious people trying to make a buck, who maybe have a chemistry degree or know a little about this or that — they order the chemicals off the internet," he said. "The powders are ordered from China and Russia, then people who want to sell them dissolve the compounds with acetone and spray them on plant material to usually sell them for $10 or $20 dollars a bag."

There are hundreds of types of varying synthetic marijuana drugs typically called "spices" or K2. They derive from research conducted by John W Huffman, a Clemson University professor who developed the first synthetic cannabinoids in the early 1990s to test the brain’s regulation of appetite, nausea, mood pain and inflammation.

Drug addiction, overdoses, and a very brief history of Heroin Show all 14 1 /14 Drug addiction, overdoses, and a very brief history of Heroin Drug addiction, overdoses, and a very brief history of Heroin Heroin – the chemical name for which is diacetylmorphine – was originally synthesized by British chemist C.R.Alder Wright (pictured overleaf) in 1874, by adding two acetyl groups to the molecule morphine, which is naturally found in the opium poppy. Drug addiction, overdoses, and a very brief history of Heroin Bayer, the German pharmaceutical company behind Alka-Seltzer and Aspirin, bought the rights to diacetylmorphine, marketing it under the name “Heroin” in 1895 because early testers said that it made them feel “heroisch” or “heroic”. Drug addiction, overdoses, and a very brief history of Heroin By 1898, it was ready for mass marketing. It was originally sold as an over-the-counter cough suppressant that didn’t have problematic side effects, like addiction (the irony) - while alternative treatments morphine and codeine did. This was before they realised that, when taken into the body, it actually converts into morphine, and is ferociously addictive. Thus defeating the object and defining what was to become a historically embarrassing moment for the company in later years. Drug addiction, overdoses, and a very brief history of Heroin By 1899 Bayer was producing a ton of Heroin and exporting the drug to 23 countries, while free samples sent to doctors and studies appeared in medical journals. It was also around this time that early reports of addiction began to surface. The company wisely released Aspirin this year, which would go on to become one of the most popular and widely used pain relief drugs in the world. Drug addiction, overdoses, and a very brief history of Heroin US medicines containing heroin were available over the counter from 1907, after the American Medical Association gave it its stamp of approval. Drug addiction, overdoses, and a very brief history of Heroin As Heroin dependency became a torrent and overdoses began to be reported, Heroin was made illegal to obtain without a prescription from a doctor in the US in 1914. Bayer lost some of its trademark rights to Heroin and Aspirin under the Treaty Of Versailles in 1919, after the German defeat in World War I. Drug addiction, overdoses, and a very brief history of Heroin In the early 1920s, a number of addicted users in New York supported themselves by collecting and selling scrap metal retrieved from industrial dumps. It was from this that the label “junkies” was born. The behavior of Heroin addicts was soon, however, to cause a concern to the public and the authorities. In 1924, it became completely illegal, and doctors were told they could no longer prescribe the drug. Drug addiction, overdoses, and a very brief history of Heroin By this point, Heroin had become popular among creative industries. Pictured left is famed actress Jeanne Eagels, who died of a Heroin overdose in 1929. Its outlawed use had pushed manufacturers underground, and the purity of the product illegal traders now used varied in quality. Drug addiction, overdoses, and a very brief history of Heroin In the UK, the Rolleston Committee Report in 1926, illegal Heroin dealers were prosecuted, but doctors could prescribe diacetylmorphine to users when they were withdrawing from it, if it would cause harm or severe distress to the patient to go without it. This would be the law until 1959 when the number of diacetylmorphine addicts doubled every 16 months between 1959 and 1968. Drug addiction, overdoses, and a very brief history of Heroin The Brain Committee recommended that only selected, specially approved doctors at specialized centres were allowed to prescribe diacetylmorphine to users in 1964. The law was further restricted in 1968, and by the 1970s, the emphasis shifted to encouraging abstinence and the use of substitute methadone. Drug addiction, overdoses, and a very brief history of Heroin In the 1980s, the UK experienced a surge in Heroin supply because of a sudden cheap influx from Pakistan (the main supplier had been – and is now – Afghanistan). Cues from popular culture – and a social downtown caused by the economic and industrial crisis in the late 1970s – created the perfect environment for the Trainspotting generation. Drug addiction, overdoses, and a very brief history of Heroin In the 1990s, Heroin use was again popularized by the rise of grunge and Britpop, while the emergence of ‘the waif’ in fashion, of which Kate Moss is often cited as the originator, would give rise to the term ‘Heroin chic’. In 1994, the Swiss began to trial a diamorphine maintenance program for users who had failed multiple withdrawal programs. It aimed to maintain the health of the user, by discouraging the use of illicit street Heroin. It was deemed a success. Drug addiction, overdoses, and a very brief history of Heroin Today, the largest producer of opium, needed to create Heroin is Afghanistan. This is closely followed by Mexico, who increased their rate of production sixfold between 2007 and 2011. Diacetylmorphine is a controlled, Class A substance in the UK, but continues to be used in palliative care for the treatment of acute pain, such as in severe physical trauma, post-surgical and chronic pain, as well as relieving sufferers of terminal illnesses. Drug addiction, overdoses, and a very brief history of Heroin Key figures continue to campaign for greater sympathies and better treatment of Heroin addicts as they attempt to rehabilitate themselves and re-enter society. Russell Brand’s Give it Up Fund, run in conjunction with Comic Relief, aims to provide financial aid to help people remain free from substance abuse by setting up support groups. "It's integral that people entering a life of abstinence after the chaos of addiction have stability, support and a role to play in the wider community," he said.

Synthetic cannabinoids have since found their way into recreational drugs like K2, which began being seen in overdoses in the US and UK around 2009.

The effects of taking K2 are far different from that of actual marijuana because weed includes mitigating compounds that reduces its toxicity on brain receptors.

What’s more, whereas marijuana has just one compound that causes psychoactive effects, synthetic marijuana typically has between three to five. And unlike weed, K2 is designed to activate 100 per cent of a brain receptor, whereas cannabis has a much weaker effect.

“K2 is meant to fully activate the receptors, so they’re much more efficacious at activating those than THC,” Mr Prather continued. "It’s a much bigger activation, no mitigating compounds to remove toxicities and an overall much bigger bang."

Outbreaks of synthetic drug overdoses have become a constant news story, with thousands of people being sent to the emergency room each year across the country for issues related to ingesting K2 and other products. At one point two years ago, New York City was seeing nearly 40 people hospitalised on a daily basis due to K2.