It sounds like the script of a typical spy movie. The baddie sends a letter laced with a suspicious powder, promptly dispatching the receiver to an early grave. However this week, such letters have become a talking point in the media discourse in Pakistan as judges find themselves on the receiving end of these missives.

Earlier this week, all eight judges of the Islamabad High Court (IHC) received letters laced with a suspicious powder. Sources said the letters, mailed through Pakistan Post, carried a threatening symbol and accused the judges of being responsible for problems faced by the people of Pakistan. According to the FIR, a white powder was discovered in the envelopes.

Some of the police officials who came into contact with the powder experienced some side effects, including irritation, sources told Dawn.

The next day, similar letters arrived in the Supreme Court and the Lahore High Court (LHC). Like those received by the IHC judges, those sent to the top court also contained a suspicious powder. The FIR described the substance as a “white powder like chemical”. Meanwhile, police did not comment on whether the missives sent to the LHC judges contained any toxic chemical.

Today, it emerged that another LHC judge received a suspicious letter, although there was no comment on whether it contained any chemical substance or threats.

In all, 18 judges of the Supreme Court and high courts have received the letters.

As this was written, all of the letters have been sent to the laboratory for testing and the government has also promised to probe the incident. But why is this “powder” kicking up such a storm, what exactly could it be and what exactly are the “powder letters”?

Kinds of powder

Until the test results come back from the laboratory and an official statement is issued, one cannot definitively say what the powder is.

The powder in question could be one of a litany of hazardous agents, including anthrax, ricin, powdered cyanide and arsenic trioxide. Alternatively, the powder could be much less sinister in nature, such as talcum powder or baking soda.

Some of the letters received by the judges mentioned the word “Bacillus Anthracis” which causes anthrax, a serious infectious disease. According to the US Centers for Disease Control (CDC), people get infected when anthrax spores enter the body.

“This can happen when people breathe in spores, eat food or drink water contaminated with spores, or get spores in a cut or scrape in the skin,” the CDC says.

The different types of anthrax infection — cutaneous anthrax (contact through skin), inhalation anthrax, gastrointestinal anthrax and injection anthrax — produce varying symptoms which can manifest anywhere from one day to two months after infection, the CDC says.

“All types of anthrax have the potential, if untreated, to spread throughout the body and cause severe illness and even death,” it says.

According to the CDC, the “microscopic spores could be put into powders, sprays, food, and water”, and “could be placed in letters and mailed” as a means of dispersal.

However, this is not the only deadly white powder that exists. Ricin — a poison extracted from castor seeds — has also been used in the past.

According to the CDC, if a person inhales or ingests a significant amount of ricin, they would suffer a host of symptoms ranging from respiratory distress to vomiting and bloody diarrhoea, which could lead to death. However, the major symptoms of ricin poisoning depend on the route of exposure and the dose received, though many organs may be affected in severe cases.

“Initial symptoms of ricin poisoning by inhalation may occur as early as 4-8 hours and as late as 24 hours after exposure. Following ingestion of ricin, initial symptoms typically occur in less than 10 hours,” the CDC says.

On the other hand, arsenic trioxide, another powdered chemical used in smelting, can prove fatal if even 70 milligrammes is ingested, the CDC says. However, it is also used as an intravenous drug to treat acute promyelocytic leukaemia, according to a medical review on drugs.com.

The short-term symptoms of arsenic poisoning include vomiting, diarrhoea, abdominal pain and in the most extreme cases, death, says the World Health Organisation (WHO). The long-term symptoms include skin lesions and the onset of cancer in different parts of the body. However, long-term cases require exposure to arsenic for far longer periods of time, either through the consumption of water contaminated with arsenic or through exposure at smelters and other industrial sites. Arsenic is present in the groundwater of many poorer nations, including Pakistan, according to the WHO.

At the same time, the CDC states that arsenic poisoning through exposure in the workplace “occurs infrequently”, adding that “recognised poisoning more commonly results from unintentional ingestion, suicide, or homicide”.

Then there is potassium cyanide, which can bear a granular appearance akin to that of sugar and releases hydrogen-cyanide gas, which is “a highly toxic chemical asphyxiant” and affects vital bodily systems, the CDC says.

The US agency says exposure to potassium cyanide can be “rapidly fatal” and it can affect the body through contact with the skin, inhalation or ingestion.

There is a chance the powder could also be mercuric chloride, a powdered form of the naturally occurring element. According to the Australian Department of Climate Change, Energy, the Environment and Water, mercuric chloride is an “odourless, white powder or crystal” and often used in the manufacture of disinfectants. It is also soluble in water.

It further says that the “nervous system is very sensitive to all forms of mercury”, with extreme exposure potentially causing brain and kidney damage. Mercury and its compounds can enter the body through ingestion or contact with skin, similar to the aforementioned powders.

Bioterrorism

The word ‘bioterrorism’ is described by Merriam-Webster as “terrorism involving the use of biological weapons”. Here are some of the most notable instances of powder being used to harm people and spread fear.

In 2001, shortly after the 9/11 terrorist attacks, anonymous letters laced with anthrax spores began arriving at media companies and congressional offices. Over the next few months, five people died while 17 others were infected.

In 2012, it emerged that a parcel received at the official residence of then-prime minister Yousuf Raza Gilani in October of the previous year carried deadly anthrax.

In 2013, ricin-laced letters were sent to then-US president Barack Obama as well as a US senator and a judge.

Just last year, around 100 letters containing a white powder were received by state legislators and public officials across the US state of Kansas.