Poisoning with biocidal products before and after the COVID-19 pandemic: report from the Croatian Poison Control Centre

We analysed all records of telephone calls to the CPCC, which provides a 24/7 telephone consultation service to the entire population of Croatia (about 3.8 million), and then extracted the data from cases of suspected or symptomatic poisoning in humans by products containing a biocide as an active substance. For products whose trade name was reported, we consulted the Material Safety Data Sheet (MSDS) of the Croatian Institute for Public Health (15) and the Register of Biocidal Preparations of the Croatian Ministry of Health (16) to obtain information about the type and active substances.

The collected data were divided into the four main groups based on product types (Table 1) and analysed in detail for age of the poisoned person, circumstances of exposure, route of exposure, and clinical manifestations. The age groups included infants (up to 23 months old), preschoolers (2–5 years-olds), school children (6–12 years), adolescents (13–17 years), and adults (18 years and older). Symptoms were divided into four categories according to clinical manifestations. The “no symptoms” category refers to cases in which the patient or a parent did not report any symptoms at the time of the call, “mild to moderate symptoms” to those involving mild to moderate digestive tract irritation (vomiting, and diarrhoea) or eye, skin, or respiratory system irritation, “severe symptoms” to serious central nervous system disorders, corrosive damage to the gastrointestinal tract, eyes or skin, severe respiratory symptoms, and “unknown” to cases where symptoms were not specified during the call.

Between 2019 and 2024, we received 1320 calls reporting human poisoning by biocides. Table 2 breaks them down by year and biocidal product type and shows that disinfectants and pest control products accounted for nearly all biocide poisoning cases (99 %) and that disinfectant poisoning incidence increased steadily by 2024.

Tables 2 and 3 show the fluctuation of calls reporting poisoning with specific groups of biocidal products over the analysed period. Specifically, of 867 disinfectant cases, 325 (37.5 %) involved hygiene products applied to the skin or scalp with the primary purpose of disinfection. In line with our earlier preliminary report (4), the number of reported poisonings with hand disinfectants increased over the pandemic years 2020 and 2021 in comparison to the pre-pandemic 2019, while a mild decrease was seen in the years following the height of the pandemic (2022–2024), although the number of cases remained higher than in the pre-pandemic 2019. The increase from 2019 was significant for both periods that followed Table 3, P<0.001) but we also observed a significant increase between the pre-pandemic period (2019) and the height of the pandemic (2020–2021) (P<0.001), and a significant drop between the height of the pandemic (2020–2021) and the period that followed (2022–2024) (P<0.001).

Poisoning with disinfectants and algaecides not intended for human use – largely surface disinfectants – accounted for the largest portion of cases in this group of products (62.5 %), and the trend increased significantly in the years following the height of the pandemic (2022–2024) (P<0.001). In other words, while the number of poisonings with hand sanitisers peaked during the height of the pandemic, the increase in poisonings with surface disinfectants occurred with a delay, and is probably the main reason for the observed significant increase in the total number of cases of poisoning with biocidal products (Table 2, P=0.032)

Poisonings with hygiene products were the most common among infants (35.20 %) and preschoolers (29.8 %), followed by adults (27.6 %). Most were accidental poisonings cases (84.6 %), and the most common route was ingestion (85.53 %), while inhalation accounted for only 6.7 % of cases. Asymptomatic cases accounted for 58.7 % of calls, while 39.1 % reported mild symptoms, manifested as mild irritation of the gastrointestinal mucosa. Severe symptoms were reported in a single case of attempted suicide in an adult patient who ingested a large amount of 96 % ethanol, resulting in impaired consciousness.

As regards disinfectants and algaecides not intended for human use, accidental poisonings accounted for 74.4 % and mostly affected adults (55.9 %). Ingestion was the predominant route of exposure (52.39 %), similar to hygiene products, but inhalation exposure was much greater than with hygiene products, accounting for 37.1 %. Most poisonings were reported asymptomatic (52.5 %), while 42.3 % had mild symptoms, most often manifested as mild irritation of the gastrointestinal tract and respiratory mucosa. Severe symptoms were reported in 15 cases. Nine of them involved severe respiratory disorder after accidental inhalation of fumes of chlorine disinfectant and or hydrochloric acid (dyspnoea, wheezing and/or hypoxia, pulmonary oedema, vomiting) or temporary vision loss and headache caused by gluaraldehyde-based fumes. CPCC has repeatedly been receiving such calls describing severe symptoms over chlorine inhalation, because the users mixed products containing hypochlorites and hydrochloric acid to clean the bathroom despite our efforts to raise awareness and educate the general population about the dangers of such practice (18, 19). The six remaining severe cases concerned ingestion, mostly of inorganic acids and alkalis in a suicide attempt, which resulted in gastrointestinal corrosive injury.

A similar trend in disinfectant poisoning was reported by the French Poison Control Centre, which noted a significant increase in exposure to household cleaning products containing biocides and alcohol-based hand sanitisers between 2018 and 2020 (20). The Italian Poison Control Centre reported a significant increase in the number of poisonings with household disinfectants in 2019 and 2020 (21, 22). Kweon et al. (23) analysed the 2017–2021 annual reports issued by the American Association of Poison Control Centers (AAPCC) and had similar findings of hand sanitiser poisonings to ours, inasmuch as they mostly affected children (23). As regards disinfectants not intended for human use, Ghai et al. (24) analysed reports by the California Poison Control System from 2015 to 2021 and, like us, found that adults were affected the most (65 %).

We had no reports of poisoning regarding other types of disinfectants, namely those used in veterinary hygiene, food and animal feed areas, or disinfectants for drinking and potable water (see Table 1).

As regards pest control products, a total of 440 reported poisoning cases were spread more or less evenly across 2019–2024, which suggests no increasing or decreasing trends (Table 3). Most (64.3 %) involved insecticides, acaricides, and products to control other arthropods and most affected children (47.5 %; 25.2 % infants and 22.3 % preschoolers), followed by adults (46.2 %). The majority were accidental poisonings (87.3 %), and 5.7 % were suicidal attempts. Ingestion (63.25 %) was the most common route of exposure, while inhalation accounted for 21.5 %. Most cases of poisoning with insecticides, acaricides, and products to control other arthropods were asymptomatic (61.8 %), 36.4 % caused mild, and four cases had severe symptoms, like intensive vomiting, brief loss of consciousness, and dyspnoea. Three such cases were related to inhalation or ingestion of synthetic pyrethroids (permethrin, alpha-cypermethrin), with developed symptoms. One case involved suicidal organophosphate poisoning with dimethoate-based insecticide.

In the US, Power and Sudakin (13) reported that 35.8 % of all pyrethrin and pyrethroid poisonings affected children between 2000 and 2005, which is in line with our results, just like the share of accidental (93.4 %) and suicidal poisonings (6.54 %). However, their data indicate a yearly increase in exposure to pyrethrins and pyrethroids, whereas our findings show consistent incidence.

In terms of prevalence, second to insecticides/acaricides/other anti-arthropod products were rodenticides with 119 (27.1 %) reported cases, 70.6 % of which were accidental and 14.3 % suicide attempts. They prevailed in children (49.5 %; 21 % in infants and 28.5 % in preschoolers), followed by adults (39.5 %). As expected, the most common route was ingestion (89.1 %), and 78.9 % of cases were asymptomatic, while 20.1 % had only mild symptoms. The only case with severe symptoms was an adult female who ingested an unknown amount of probably concentrated, bromadiolone-based rat poison in liquid form. The patient was found unconscious and admitted to intensive care, where she was successfully treated with vitamin K1 and plasma.

Identical, 49.5 % prevalence of rodenticide poisoning in Norwegian children was reported by Soleng et al. (12) for 2005–2020, and the share of suicidal cases was also similar to ours (15 % in Norwegian report) (12).

We established only six cases of poisoning with molluscicides, vermicides, and products to control other invertebrates, and all were accidental (Table 3).

Accidental were also all 32 poisonings with repellents and attractants for human or animal use, and all were owed to improper storage. Twenty-eight cases involved infants and preschoolers, two involved school children, one an adolescent, and one an adult.

As for other pest control product types, namely avicides, piscicides, and products to control other vertebrates, none were involved in the reported poisonings.

Poisoning with preservatives and other biocidal products was but sporadic across the analysed years (Table 2). Of the 10 reported cases, six involved wood preservatives, and four construction material preservatives. Eight cases were accidental household poisonings, and the remaining two were related to occupational exposure. All involved adults.

As for other biocidal products, all three poisoning cases involved embalming and taxidermist fluids used for the disinfection and preservation of human or animal corpses. All three affected adults through occupational exposure, specifically in a pathological laboratory, where laboratory technicians storing samples inhaled formaldehyde vapours.

The main limitation of our study is that the information on clinical signs and symptoms we received at the time of the call was limited and often provided by a lay caller. This may have diminished the reliability of poisoning severity assessment. During the call, we are focused on as quick and as accurate assessment of health risks as possible. Whether the product is a biocide is not crucial information for patient treatment, so the number of poisonings with biocidal products may have been underreported, as we present only the cases for which we were certain they involved biocides, based on the product name, composition, and description of use provided by the caller.

Regardless of this limitation, this is the first study covering poisoning with all biocidal product types (22 in total). To the best of our knowledge, there are no other reports of a similar scope on post-pandemic trends in poisonings with biocidal products from other countries.

Our results suggest that poisoning with biocidal products remains a public health problem. The most prevalent was the poisoning with disinfectants and pest control product, and we notice an increasing trend in poisoning with surface disinfectants, even after the peak of the pandemic. Hand disinfectants show an opposite, declining trend after the pandemic, but the numbers remain higher than before the pandemic. What raises particular concern is the high share of child poisonings with hand disinfectants, rodenticides, and insecticides, which calls for better labelling and packaging and for restricting the availability of biocidal products in households. We hope that our findings could inform additional preventive measures to reduce the risk of accidents and to ensure safe use of biocides in everyday life and at workplaces.