Health
Rainy season: How poverty drives families to toxic mosquito killers
As the rainy season fuels mosquito breeding and malaria cases, many low-income families in Nigeria are turning to cheap, unregulated homemade insecticides sold for as little as N300 to protect themselves against mosquito bites, a choice that toxicologists and health experts warn could be exposing them to chemicals capable of causing breathing difficulties, birth defects, infertility, and long-term organ damage. JANET OGUNDEPO reports
One cold night in July 2022, at 2 am, while many Lagos residents were snuggled in bed, a mother of two, Mrs Yetunde Omotunde, was gasping for breath.
Omotunde, a local herbal seller, said she was seven months pregnant at the time and had tried as much as she could to protect herself from mosquito bites.
To achieve this, she bought several 30ml bottles of locally formulated insecticide touted to be “good” at the market where she sold her wares.
She never imagined that the insecticide she bought to ward off mosquitoes that persistently swarmed her one-room apartment nestled in the Oshodi area of Lagos State would give her a near-death scare.
“When I was pregnant with my first baby, I bought lots of these locally formulated insecticides at the market. The instruction I was given was to add a little water to the insecticide, spray it in the room while covering my nose and then leave the room for 30 minutes,” she said.
The fair-complexioned middle-aged lady recounted the encounter to PUNCH Healthwise, “On that night, I came back into the room after 30 minutes, and the insecticide odour still lingered in the room. So, I turned on the fan and went to bed.
“But when I woke up around 2 am, I was struggling to breathe and was choking. My husband was trying to position me in a way that would help me to breathe. After several attempts, I was better, but when the day broke, I couldn’t understand how I was feeling.”
Omotunde, who is now a mother to a four-year-old girl and a nine-month-old boy, visited the hospital the next morning after the night’s encounter left her weak and dizzy.
During her consultation, the middle-aged woman said the gynaecologist, after a series of questions, suspected the locally formulated insecticide she sprayed in her poorly ventilated room as the cause of her discomfort.
She said the doctor calmly explained to her that the chemicals mixed in the homemade insecticides were not safe, especially for pregnant women, and advised her to never use them again.
“That episode ended my marriage with these homemade insecticides. The smell is too strong and pervades the house for a long time,” Omotunde said.
The mother of two said her house has an open drainage a few meters to her window, making her room a sanctuary to mosquitoes during the rainy season.
Despite that, she ensures her children sleep under a treated mosquito net to protect them from malaria, regardless of the heat and space.
For her and her husband, who sells building materials, they rely on the mosquito net at their windows and door, as well as the whirling of their multiple fans to keep the mosquitoes at bay.
Almost choked to death
The desire for a long-lasting and “strong mosquito killer” pushed the mother of two boys, aged 11 and nine, Shalewa Iretiola, to purchase a locally formulated insecticide.
The rhyme, “E dey kill cockroach, e dey kill mosquitoes, on pa ayan, on pa efon, on pa idun,…” was well known among the young and old on her street in Ijadu, in the Mile 12 area of Lagos State.
His neighbours had attested to the “work” of the insecticides, so Iretiola decided to buy some.
The frozen food vendor said she sprayed the insecticide in her one-room apartment on Ijaiye Road in Lagos’ Ojokoro area before leaving for her stall that morning, knowing that she and her family would not return home until late in the evening.
But when they returned, the lingering odour of chemicals greeted them.
Iretiola said she turned on the fan and opened all the windows for about 30 minutes to ensure the room was conducive. While they all retired to their beds and mats, the recurrent sputters of her children’s chesty cough woke her up.
In the morning, Iretiola’s boys seemed better, so she dismissed the cough. But when it persisted for about two weeks, she finally began to look into what went wrong.
“I used the insecticide about three times and they seem to drive away the mosquitoes, but every night, my children would cough intermittently. I began to get worried. It wasn’t until much later that my husband mentioned that the cough started when I began to use the insecticide,” she said.
The frozen food vendor said she had to stop using the insecticide and opted for a mosquito coil.
“I can’t afford the branded insecticides. The least of them costs about N2,500 and I’ll only use it twice and it’s finished. I’ve continued with the coils, though it has its side effects too,” Iretiola said.
Helen Onah, who also patronised the product, said the odour was so strong that she was advised to wash her room afterwards, as the insecticide odour would not simply go.
She had paid N500 for her bottle and she began coughing shortly after applying it.
Some of the bottles inspected by PUNCH Healthwise carried no proper branding, with a few bearing handwritten or printed claims of killing mosquitoes, cockroaches, ants and other insects, despite having no regulatory approval or listed ingredients.
Sells but doesn’t use
A seller of locally formulated insecticides, Mrs Temilade Ariyo, confessed to PUNCH Healthwise that while she sells the products, she does not use them in her own home.
Her reason was that the insecticide has a strong odour that lingers for a long time after spraying. Although Ariyo said she was not involved in producing the insect repellents, she understood the market demand, buys the product in bulk and resells the 30ml bottles for N400, far cheaper than branded alternatives.
She said sales rise sharply during the rainy season as more families look for affordable ways to keep mosquitoes away.
Cost a major barrier
The rainy season across the country starts in April and lasts until October. During this season, there is usually a spike in mosquitoes due to multiple stagnant pools of water, blocked drains, potholes and overgrown grasses, which serve as breeding grounds for the mosquito larvae. Consequently, there is an increase in malaria cases during this period.
Due to low purchasing power and rising costs of food, transportation, and rent across the nation, many low-income families have been pushed to seek cheaper alternatives for essential products, often unaware of the implications for their health.
Unarguably, many Nigerians, in a bid to have another source of income, venture into the local production of insecticides.
Respondents who spoke to PUNCH Healthwise confirmed that they could buy a 30ml bottle for N400 and use it twice, instead of buying a 300ml bottle of the branded insecticide spray that sells between N3,000 and N8,000 in the local market.
Findings by PUNCH Healthwise revealed that the locally formulated insecticides contained chemicals, some of which were volatile and listed as restricted chemicals by the National Agency for Food and Drug Administration and Control.
At Kazeem Street, Ojota
During a visit to the “chemical market” at Ojota, Lagos State, PUNCH Healthwise observed the improper storage of volatile chemicals and the lack of personal protective equipment worn by the sellers and “mixers.”
In a conversation with a seller of insecticide and soap chemicals at the market, identified as Victor, formalin, ethanol and a mix of a popular organophosphate pesticide.
“When I mix it for you, it’s about three chemicals, and you will just add kerosene to it to fill up the 50cl bottle. This is where those who do sell them in the streets buy them,” he said.
Victor, who admitted that the odour of the chemicals was strong and choking, advised that they be sprayed in the morning so that by the time residents returned home in the evening, the smell would have dissipated.
While users are exposed to the risks, Victor noted that those who sell and mix the chemicals face an even greater danger of falling ill.
Surprisingly, although Victor mixed the cheapest quantity of the insecticide for our correspondent, he wore neither a face mask nor gloves.
The bottles from which the chemicals were dispensed were unlabelled, forcing him to identify their contents by smell and, in some cases, by colour.
“I’m used to the smell, but I have to take medications every day due to the side effects of constantly perceiving the chemicals,” he said.
Our correspondent observed how the storage shops, where all the activities are conducted, lacked a proper ventilation system.
Restricted chemicals yet sold openly
Three years ago, on October 11, 2023, the National Agency for Food and Drug Administration and Control released a list of 53 restricted chemicals. Yet PUNCH Healthwise found that some of these chemicals continue to be sold without restraint in the open market.
Formaldehyde and paraformaldehyde, for instance, is the 25th item on that list. Despite this, formaldehyde, popularly known as formalin, is openly sold to customers who request it.
Cheap insecticides, hidden dangers
Providing expert insight into the matter, a Professor of Environmental Health and Toxicological Risk Assessment at the Ladoke Akintola University of Technology, Ogbomoso, Olayinka Adewoye, warned that the chemical composition and concentrations in homemade or locally formulated insecticides are unknown and unregulated.
He explained that while many households turn to these products because they are cheaper and more readily available, the mixtures, commonly made with chemicals such as formalin, ethanol, and kerosene, expose users to substances that have never undergone any safety evaluation.
“Exposure to the products could trigger respiratory irritation, breathing difficulties, skin reactions, and eye irritation, particularly among children, pregnant women, the elderly, and pets. Children, especially those under five, are at heightened risk of poisoning because of their developing bodies and increased vulnerability to chemical exposure,” he said.
Adewoye noted that the danger was not limited to occasional use, warning that continuous inhalation of the chemicals, particularly in poorly ventilated rooms, could result in chronic exposure with symptoms including persistent irritation of the nose and throat, coughing, chest tightness, breathing difficulties, headaches, dizziness, fatigue, poor concentration, nausea, and sleep disturbances.
“Although many people dismiss these symptoms as temporary, the toxic effects may accumulate over time,” he said.
He cautioned that repeated exposure could have long-term consequences, including reduced lung function, the development or worsening of asthma, hormonal disruption, and weakening of the immune system, adding that some of these effects could remain hidden for years before manifesting as serious health problems.
A major concern, he said, was the lack of proper labelling, dosage instructions, and regulatory approval for many of these products.
“Without information on ingredients, safe concentrations, precautions, or usage directions, consumers are unable to determine whether they are exposing themselves and their families to dangerous levels of toxic chemicals,” he said.
Adewoye explained that, unlike registered insecticides, which are tested to ensure active ingredients are used at safe concentrations, homemade products are often prepared through arbitrary mixing of chemicals, increasing the risk of toxicity.
To reduce mosquito exposure while limiting chemical risk, the toxicologist recommended the use of original insecticide-treated bed nets, installation of window and door screens, elimination of stagnant water around homes, proper environmental sanitation, and improved indoor ventilation.
Where insecticides must be used, he urged consumers to purchase only approved and properly labelled products, follow recommended usage instructions, ensure rooms are adequately ventilated after spraying, and keep children, pregnant women, pets, and food away during application.
Adewoye also called for stronger regulatory enforcement, including regular market inspections, public education on safe pesticide use, and sanctions against manufacturers and sellers who flout safety standards.
Children at risk of lung irritation – Paediatrician
The Head of Paediatrics at the Federal Teaching Hospital, Katsina, Dr Abdurrazzaq Alege, said children were more vulnerable to these chemicals because their lungs and airways were still developing and less able to cope with toxic exposure.
He explained that many of the substances reportedly used in locally produced insecticides, including kerosene, ethanol, formaldehyde, and other volatile compounds, could irritate the eyes, skin, and respiratory tract.
“Children, when their lungs are still growing, they have a small airway, and this predisposes them to so many things that can come in contact with the airway. When children are exposed to this, they can have some bad experiences, which can include irritation, even of the skin and the eyes,” he said.
Alege warned that inhaling the chemical vapours could trigger bronchospasm, a sudden narrowing of the airways that makes breathing difficult.
“Inhaling some of these chemicals can have an effect in triggering bronchospasm, that is, the airway will just start to go into spasm, and then they have respiratory difficulty, and with that, some of them can even choke,” he said.
He expressed particular concern about kerosene, describing it as a volatile hydrocarbon capable of causing lung inflammation.
“Kerosene easily gets into the airway and, apart from choking the child, it also causes inflammation within the lungs, and with this, you have what we call chemical pneumonitis,” he said.
He noted that symptoms such as coughing, fever, and breathing difficulties sometimes appeared several hours after exposure, making it difficult for parents to connect them to the insecticide.
Beyond the immediate effects, Alege warned that repeated exposure could lead to recurrent chest infections and worsen underlying conditions such as asthma and allergies.
He also raised concern about formaldehyde specifically, citing its association with certain cancers.
“Some studies have shown that formaldehyde has been linked to some cancers. Cancers of the lungs have been associated, and even some blood cancers have been associated with, formaldehyde. So far, we know that this is with prolonged regular exposure,” he said.
He noted that the risk was compounded by poor housing conditions, as many families who depend on these cheaper insecticides live in overcrowded, poorly ventilated rooms.
“Most of these children, too, are living in a not-too-ventilated room. So staying in these mixed vapours, all these chemicals will become more concentrated in the environment, and it worsens the situation of the chest,” he said.
He also flagged the common practice of storing these insecticides in used beverage and water bottles without labels, warning that it increased the risk of accidental poisoning.
“The children also stand the risk of accidentally swallowing this chemical. We have seen them,” he said.
Alege called for proper regulation and standardisation of locally manufactured insecticides, alongside stronger public awareness campaigns.
“There have to be regulations on how to prepare and mix these mixtures, not just random mixtures. There has to be a monitoring mechanism or a standardisation by a regulatory body,” he said.
He also advised against spraying insecticides in occupied rooms, particularly at bedtime.
“It will not be wise for us to spray in the room at bedtime when we are still in the room. It can have adverse effects on everyone and especially children,” he warned.
Exposure linked to birth defects, fertility risks
A Professor of Obstetrics and Gynaecology at Usmanu Danfodiyo University, Sokoto, Abubakar Panti, warned that exposure to household insecticides during pregnancy, especially during the first trimester when foetal organs are still forming, could lead to birth defects in the baby.
He explained that certain chemical groups commonly found in insecticides, including organophosphates, carbamates, and pyrethroids, have been associated with birth defects such as neural tube abnormalities and limb malformations and may also increase the risk of low birth weight, preterm birth, miscarriage, and stillbirth.
Beyond physical birth defects, Panti said prenatal exposure had been linked to developmental and neurological problems in children, including developmental delays, reduced cognitive function, attention deficit disorders, hyperactivity, autism spectrum disorders, and lower intelligence quotients.
“Prolonged exposure to active ingredients like pyrethroids or organophosphates can cause developmental problems in the baby’s brain and nervous system. It can also lead to low birth weight, preterm birth, miscarriage and hormonal imbalances that may affect foetal development,” he said.
He advised families to ensure adequate ventilation after spraying and urged pregnant women to avoid direct exposure wherever possible.
“When somebody wants to apply for them, maybe your husband applies at home, you all leave the house, and when the smell has gone down, you come back. That is safer. But when the pregnant woman wants to apply it herself, she has to really protect herself, wear a mask and protective clothing,” he said.
Panti said growing evidence suggested that insecticide exposure could contribute to infertility in both women and men by disrupting hormonal balance and damaging reproductive organs.
“These chemicals can affect the ovaries, fallopian tubes and uterus. They may reduce ovarian reserve, interfere with ovulation and increase the likelihood of miscarriage or infertility,” he said.
The gynaecologist added that men were equally vulnerable, with insecticide exposure linked to reduced sperm count, poor sperm motility, abnormal sperm morphology, and hormonal disruptions affecting fertility and libido.
“Evidence has shown that men exposed to pesticides, whether through occupation or environmental exposure, tend to have poorer sperm quality compared to those who are not exposed,” he said.
To minimise risk, Panti advised households to adopt non-chemical pest control methods where possible, including insecticide-treated nets, window screens, and improved environmental sanitation, alongside the use of protective equipment such as gloves and masks when handling insecticides.
“Minimal exposure is key. People should use safer alternatives where possible, follow safety instructions carefully, and seek medical advice if they experience significant exposure,” he said.
NAFDAC mum
Efforts to get the reaction of NAFDAC were unsuccessful as the agency’s Resident Media Consultant, Sayo Akintola, promised to revert with the response of the Director in Charge.
But he had to do so as of press time.
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