Why Vendors Dye Fish, Meat Using Harmful Chemicals to Fake Freshness
By Obajoseph Michael
Mrs. Fatimetu Dirisu has a simple test for anyone buying fish in a Nigerian market: wash it. If the water turns pink or red, throw it out immediately. It is a scam and a health hazard.
Dirisu may not be a food scientist but she is a consumer of fish and meat who has learned the hard way. She has gotten to know from experience, that the fresh-looking fish on display at many Nigerian markets, may actually not be a fresh fish but a chemical illusion. Yes, the buyer may see the red gills, the bright eyes, the firm flesh, the absence of flies, the lack of the usual fishy smell, indeed, investigation by the magazine’s Reporter show that these are not signs of freshness rather they are in most cases sign of use of poisoning chemicals.
Across Nigeria, from Lagos to Port Harcourt and from Kano to Onitsha, fish and meat vendors especially are using industrial chemicals to mask decay. Formalin, the same chemical used to preserve dead bodies in mortuaries, is being sprayed on fish and meat to keep flies away and extend shelf life span. Toxic dyes are also being injected or applied to make fish look freshly caught.
Also, Sniper, a brand of dichlorvos pesticide, is equally being used to kill insects and preserve perishables. Sodium hydroxide, kerosene, and carbide are being deployed to keep frozen fish and poultry products from spoiling. The result is a food safety crisis that is slowly poisoning millions of Nigerians, one meal at a time.
The National Agency for Food and Drug Administration and Control, NAFDAC, has been warning about this for years but nothing appeared to have changed. In August 2021, the agency raised a public alarm. Its Director General, Professor Mojisola Adeyeye, revealed that the agency had discovered that formalin was being used by some meat and fish sellers to preserve their products. The warning was clear. Formalin is not a food preservative. It is a poison. Ingestion or prolonged exposure to it can cause severe health consequences, including cancer, organ damage, and death.But the warnings did not stop the practice.
By 2025, the crisis had grown so severe that it reached the floor of the National Assembly. On October 22, 2025, the House of Representatives adopted a motion of urgent public importance moved by Honorable Chike Okafor, representing Owerri Federal Constituency of Imo State. The motion called for an investigation into the alleged use of harmful chemicals as preservatives for frozen foods in Nigeria. Okafor did not hold back. He informed the House about the persistent public outcry over the alleged use of dangerous chemicals such as formalin, sodium hydroxide, sniper, kerosene, and carbide as preservatives in frozen fish, prawns, shrimp, meat, and other food items in Nigerian markets. He stated that reports from regulatory bodies, health experts, and media investigations revealed that these chemicals, commonly used for embalming corpses, industrial processes, and ripening fruits, were now being used to prolong the shelf life of perishable foods. He further said in larment, that the use of the chemicals pose serious health risks to consumers, including the potential for developmental disorders such as autism in children, cancer, organ damage, and other life threatening health conditions for countless Nigerians, as documented by the Nigerian Medical Association.
Curiously, most frozen products imported into Nigeria are preserved using carcinogenic substances. These are substances or radiations that are agents directly involved in causing cancer. Some eateries use certain harmful substances including dimethylpolysiloxane, a silicon-based polymer used in various applications like lubricants, conditioning agents, and de-foamers, to prepare chicken. Some also use tertiary butyl hydroquinone, a chemical preservative so deadly that just five grams can kill a human being.
Okafor lamented that the relevant agencies saddled with this responsibility had been allegedly complicit and sometimes overlooked the dangerous menace. Despite previous resolutions and warnings, the illegal practice persists
For instance, the Food Safety Bill of 2023, mandates agencies like NAFDAC, the Standard Organisation of Nigeria, and the Federal Ministry of Health to safeguard public health. These agencies have a mandate to regulate and monitor the safety of food products in Nigeria, but despite the law on food safety, nothing has changed.
The situation according to this magazine’s investigation is moving from bad to worse. Even with water everywhere there is hardly good water that has no too much iron or other elements dangerous to the body to drink in rural and urban cities. But the use of harmful chemicals as preservatives has remained the worse and it continue to kill Nigerians on a daily basis.
Indeed, by October 2025, when the crisis had grown so severe that it was brought to the floor of the National Assembly, the House was not only alarmed, it was moved to act. The lawmakers mandated the Committees on Nutrition and Food Security, NAFDAC, Safety Standards and Regulations, and Agriculture to jointly investigate the alleged use of harmful chemicals as preservatives in frozen foods across the country and report back within four weeks for further legislative action. The National Assembly then called on the Federal Ministries of Health and Agriculture and Food Security, NAFDAC, SON, and other relevant agencies to appear before the investigative committee to provide valued information on their efforts to curb the dangerous trend. Nothing has changed.
It would be recalled that in 2022, a study by the University of Ibadan found dangerous levels of pesticide residues in frozen foods. Despite these worrisome past reports, the practice persists. As Okafor told his colleagues, we are now facing what can only be described as the systematic poisoning of our populace. There is a dangerous development today that a huge number of young men and women in Nigeria are suffering from liver damage, kidney failure, and there is a noticeable increase in the number of children suffering from autism, and the cause of these ailments are not far fetched. The social media outcry has been equally fiercfied.
It would also be recalled that in February 2026, Beatrice Senadju Boateng took to Facebook to expose what she described as a hidden danger affecting households across the country. She alleged that formalin was being used discreetly in some markets, potentially exposing consumers to grave health risks at a time when the country was already grappling with environmental challenges linked to illegal mining. She warned that many buyers may be unknowingly consuming fish laced with formalin, a substance intended for industrial and laboratory use rather than food preservation. This is not preservation, she stated. This is poisoning.Boateng questioned the absence of visible sanctions such as arrests, prosecutions or closure of businesses implicated in such conduct. If this was happening elsewhere, people would be arrested and named, businesses would be shut down; but here, we talk and move on, she wrote. Her post triggered intensified calls for thorough investigations and stronger regulatory oversight.
Indeed, this Magazine’s Reporter investigation revealed that some fish vendors apply dyes to make fish appear freshly caught. Curiously, the chemicals used are industrial dyes, containing heavy metals like lead and chromium, which accumulate in the body over time and cause cancer, neurological damage, and organ failure.
Further investigation revealed that the science behind the deception is simple and deadly. For instance, Formalin, a 37 per cent solution of formaldehyde gas in water, is a potent antimicrobial and anti-decomposition agent. When sprayed on fish or meat, it kills bacteria, prevents discoloration, and keeps flies away. Though, the fish looks fresh, it smells neutral, it feels firm, but it is slowly killing the person who eats it. Short term exposure causes watery eyes, coughing, wheezing, nausea, skin irritation, and sore throats. Long term exposure causes malignancy, leading to cancer of the nose, throat, and blood. It damages the liver, kidneys, and central nervous system. It is particularly dangerous for children, pregnant women, and people with compromised immune systems.
The dyes used to fake freshness are equally toxic. Sudan dyes, a class of synthetic azo dyes, are banned in many countries because they are carcinogenic. They have been found in palm oil in Ghana, in spices in India, and now in fish in Nigeria. When consumed regularly, they increase the risk of bladder cancer, liver cancer, and DNA damage. The heavy metals in some industrial dyes, lead, cadmium, chromium, and arsenic, accumulate in the body and cause developmental delays in children, reproductive disorders in adults, and chronic diseases that drain families and overwhelm the healthcare system. The scope of the problem extends far beyond fish.
A 2025 review publication published in the journal Foods, a peer reviewed publication by MDPI, examined chemical contaminants in marine and freshwater fish in Nigeria. The review found that while most contaminant levels reported for fish do not imply immediate health issues, iron and lead may represent potentially toxic levels in fish from specific areas, metal contamination in fish appeared to be affected by mineral deposits in the environment and industrial effluents.
The consumption of smoked Ethmalosa fimbriata, a common local fish (bonga fish), poses a higher potential carcinogenic risk than other species investigated. The review noted that heavy metal levels in fish are generally below maximum levels, but there is limited data available on persistent organic pollutants, dioxins, brominated flame retardants, and fluorinated compounds in Nigerian fish. The authors called for a more systematic sampling strategy to identify the most vulnerable species, the hotspots of contaminants, and applicable food safety control measures.
A more recent study, published in March 2026, examined essential and toxic heavy metals in fresh and smoked seafood from Kaa coastal market in Rivers State, Niger Delta. The study found that lead concentrations in smoked fish and smoked shellfish were repeatedly above the stated permissible limit of 0.30 milligrams per kilogram, with the highest values observed in smoked catfish and smoked crab. Arsenic dominated carcinogenic risk estimates, with total carcinogenic risk values ranging from 2.3 times 10 to the power of negative 4 to 4.6 times 10 to the power of negative 4. The hazard index values exceeded unity in some smoked seafood samples, suggesting potential non carcinogenic risks associated with long term consumption. Children were found to be more vulnerable to heavy metal exposure than adults due to their lower body weight.The problem is not limited to fish. In 2025, NAFDAC warned against the use of dichlorvos, commonly known as Sniper, to preserve food. Dichlorvos is an organophosphate pesticide. It is deadly. It causes cancer, death, and other debilitating health problems. Yet vendors spray it on grains, beans, and dried fish to keep insects away. If the chemical seeps into the food, it cannot be washed off completely. Yet such dried fishes are consumed by millions of Nigerians who have no idea what they are eating.
A 2025 review in the journal PMC, titled Chemical Toxicants Used for Food Preservation in Africa, identified Nigeria as a hotspot for the abuse of formalin and sodium benzoate in the preservation of fish and meat. The review documented how fishermen in Cameroon and Nigeria pour gamalin, a toxic insecticide, into water, killing aquatic life and then gathering and selling the poisoned fish. Hunters apply formalin on the bodies of killed animals to keep them from decomposing until they return to their villages. Curiously too, farmers add formalin to milk as a medicine before selling to factories.
The review also highlighted the broader context of food fraud in Africa. Sudan IV, a fat soluble dye and known carcinogen, is used as a food coloring agent in palm oil in Ghana. Melamine, an industrial chemical used as a fire retardant and plastic stabilizer, is added to powdered milk in East Africa to fake high protein content. Hydrogenated vegetable oils and sodium nitrate are abused in processed meats in South Africa. Talcum powder and melamine are used in food fraud in East Africa. The abuse of sodium nitrite in boiled meat is a problem throughout North Africa. Globally, about 57 per cent of people, of which 32 per cent are children, are estimated to develop health challenges from consuming adulterated food.Why does this continue? The answer is a toxic mix of poverty, profit, and regulatory failure. For fish vendors, especially those selling imported frozen fish that has spent weeks in transit, the pressure to reduce losses is immense. Fish that has started to spoil cannot be sold at full price. It cannot be sold at all. But few naira spent on formalin or dye can turn a loss into a profit. For the vendor struggling to feed a family, the moral calculation is simple: The customer will not know. Again, out of profit mentality, the vendors will quickly sell the fish or meat to a willing and unsuspecting customer knowing that the customer will not die immediately. Even if the customer gets sick, there is no way to trace it back to the particular fish or meat.
This is where the regulatory powers of NAFDAC, SON, the Federal Ministry of Health, and state ministries of health are called to bear after all they all have mandates to police the food chain.
Unfortunately, the magazine’s investigation revealed that enforcement is patchy, laboratory capacity is limited and Inspectors are few and often underpaid, making them susceptible to bribery.
The informal food sector, where most Nigerians buy their food, is vast and equally largely unregulated. Markets are crowded, chaotic, and difficult to monitor. Vendors can hide chemicals, dispose of evidence, and resume operations within hours of a raid.
In 2021, NAFDAC had warned meat and fish sellers to stop using formalin. Then in 2025, the House of Representatives launched a probe and of course this year 2026, social media activists and newspapers are still exposing the same practices, one expects a total change in the practice of using dyes to fake freshness of fish and meat.
The cycle of warning, outrage, and inaction repeats because the underlying conditions, poverty among vendors, weak enforcement, corruption, and lack of public awareness, remain unchanged.The consequences are already visible in Nigeria’s health statistics. The Nigerian Medical Association has documented rising cases of liver damage, kidney failure, and developmental disorders in children. Cancer rates are increasing, particularly cancers of the digestive tract, liver, and blood. While many factors contribute to these trends, the systematic consumption of formalin laced fish, dye treated meat, and pesticide sprayed grains is almost certainly one of them.
For the average Nigerian consumer, protection is limited. The advice from experts is simple but insufficient. Wash fish thoroughly before cooking. If the water runs pink or red, discard the fish. Look for the natural fishy smell. Check that flies are attracted to the fish, if they are not, something is wrong. Buy from trusted vendors.
Certainly, in a country where most people buy from open markets where provenance is unknown and regulation is absent, even precautions are inadequate, the solution requires more than consumer vigilance. It requires sustained political will. It requires funding for NAFDAC and SON to hire more inspectors, equip more laboratories, and conduct regular, unannounced market inspections. It requires prosecution and imprisonment of vendors caught using toxic chemicals, not just warnings and fines. It requires public education campaigns that teach consumers to recognise chemically treated food. It requires collaboration with international partners to inspect imported frozen fish at the point of entry, before it reaches the market. And it requires a fundamental shift in how Nigeria thinks about food safety, not as an afterthought, but as a national priority. Until then, millions of Nigerians will continue to sit down to meals they believe will nourish them, unaware that the fish on their plate may have been treated with the same chemical used to preserve a corpse. They will wash it, cook it, feed their children with it, and wonder why the cancer came, why the child stopped developing, why the kidney failed. And the vendors who sold it to them will be at the market the next day, with a fresh batch of fish, a fresh coat of dye, and a fresh spray of formalin, ready to do it all again.
The major reason for the absurdity and abuse of the law is due to weak enforcement of the law, corruption, and lack of public awareness. Again, fish and meat that have started to spoil cannot be sold at full price or may not get sold at all. But because of poverty, profit mentality and regulatory failure vendors end up selling the poisons to unsuspecting customers
Besides, prosecutions are rare and there are no convictions just as there are no penalties. When they exist, they are too weak to deter offenders.