The NPIS continues to study exposures to household products, including automatic dishwashing products, liquid laundry detergent capsules, automotive screenwashes and reed diffusers.
Automatic dishwashing tablets
The traditional tablets for automatic dishwashing machines, which are still used widely, are contained within an external wrapper that requires removal prior to loading the enclosed tablet into the machine. Soluble film automatic dishwashing tablets, unlike their traditional counterparts, require no removal from an outer protective wrapper prior to use. Soluble films used in this way have two main advantages. Firstly, the exact amount of chemicals required for the purpose is delivered once the film dissolves completely in water. Secondly, as there is avoidance of direct contact with the chemicals, the introduction of soluble film products has the potential to improve safety. That being said, the integrity of the soluble film can be compromised and the contents of the tablet can be released prematurely when in contact with moist hands or saliva.
Both traditional and soluble film tablets commonly contain a source of hydrogen peroxide (often as sodium percarbonate) and non-ionic surfactants. Other constituents in some formulations include sodium carbonate, sodium tripolyphosphate, and sodium silicate, which reduce water hardness. The pH once dissolved in water is alkaline.
Soluble film automatic dishwashing tablets
The NPIS has published the first study to investigate the toxicity of soluble film automatic dishwashing tablets,1 though some of these data were published in abstract previously.2
Telephone enquiries to the United Kingdom National Poisons Information Service regarding soluble film automatic dishwashing products were analysed retrospectively for the period January 2008 to December 2015. There were 498 enquiries relating to 488 patients. Almost all exposures occurred in the home (98.4%) and involved children aged 5 years or less (92.8%). Exposure occurred mainly as a result of ingestion alone (n=470, 96.3%); eye contact alone (n=9, 1.8%) and exposures involving multiple routes (ingestion with skin or eye contact; n=9, 1.8%) made up the remaining cases.
The majority of patients were asymptomatic following exposure (n=325, 67.4%). The most common feature following ingestion was vomiting which occurred in 121 of 474 cases (25.5%) where clinical data were available. Nausea (n=8, 1.7%) and coughing (n=6, 1.3%) were also reported; 3 patients developed stomatitis and another 5 developed a rash where ingestion alone was considered to be the sole route of exposure. Ocular exposure to the tablet contents resulted in blurred vision, eye pain or conjunctivitis in 7 of 10 patients.
In conclusion, ingestion of a soluble film automatic dishwashing tablet rarely resulted in clinically significant symptoms, which is surprising given the potential hazard of the ingredients. Hence, it seems probable that the amount of material actually ingested was very small or that most was spat out.
Traditional automatic dishwashing tablets
The NPIS has published recently a study investigating the toxicity of traditional automatic dishwashing tablets, and compared them to the soluble film product type.3
There were 503 enquiries relating to 492 patients who had been exposed to a traditional tablet. Most involved children aged 5 years or less (87.4%). The majority (78.6%) of patients did not develop symptoms after exposure; 21.1% developed minor (PSS 1) symptoms while one patient developed moderate features. Exposure occurred predominantly as a result of ingestion (n=476, 96.7%); the most common feature in symptomatic patients (n=99, 20.8%) was vomiting (70 [14.7%] cases). Significantly (p<0.0001) more adults (44.9% of 49 adults; 95% CI = 31.9-58.7) were reported with features than children (18.2% of 434; 95% CI = 14.9-22.1). There were five cases of eye contact which resulted in eye pain in two patients and eye irritation in another. Only one of 11 patients exposed dermally developed features (a rash around the mouth).
Comparison between traditional and soluble film exposures
Although exposure to both traditional and soluble film automatic dishwashing tablets rarely produced clinically significant symptoms (PSS ≥ 2), the proportion of patients that became symptomatic following ingestion of a soluble film dishwashing tablet (31.7% of 473 patients; 95% CI = 27.7-36.0) was significantly greater (p<0.0001) than that for traditional tablet (20.9% of 483 patients; 95% CI = 17.5-24.8). Vomiting was the most commonly reported feature and occurred significantly (p<0.0001) more frequently amongst patients who had ingested a soluble film tablet (25.5%; 95% CI = 21.8-29.6) than a traditional tablet (14.7%; 95% CI = 11.8-18.1).
The reasons for the difference in frequency of symptoms after ingestion of soluble film tablets and traditional tablets are not known with certainty but may relate to the relative hardness of traditional tablets which children may find difficult to bite. In addition, soluble film tablets containing a liquid may result in greater ingestion of material.
Liquid laundry detergent capsules
The NPIS has published previously detailed data on 2,133 exposures to liquid laundry detergent capsules4,5 and a report on the impact of the International Association for Soaps, Detergents and Maintenance Products (AISE) Product Stewardship Programme on the number of exposures and their severity.6
It is apparent that although the majority of patients remain asymptomatic or suffer only minor features (Poisoning Severity Score [PSS] 1), a small proportion develop features such as CNS depression, stridor, pulmonary aspiration and/or airway burns following ingestion, and conjunctivitis leading to corneal ulceration from eye exposure.4,5 As a consequence, AISE established a Product Stewardship Programme in Europe, requiring that safety measures be implemented to reduce the visibility of, and restrict access to, these detergent capsules by small children. Implementation occurred in the United Kingdom over several months during the first half of 2013.
While there was a significant difference (p=0.0002) between the mean number of annual exposures (469.4) reported between 2008-2012 and the mean number reported between 2014-2015 (403.5), the number of exposures was decreasing steadily prior to implementation of the Programme in 2013, which did not impact this fall from 2013 onwards. In addition, the number of exposures per million units sold was not impacted by the Programme. There was no significant difference (p=0.68) between the mean number of exposures (11.8) with PSS ≥ 2 reported between 2008-2012 and the mean number (13.0) reported between 2014-2015. Although there was a 28.7% decrease between 2010-2012 and 2014-2015 in the number of exposures with PSS ≥ 2 per million units sold, this decrease was not statistically significant (p=0.18).
Thus, there is no evidence that the Product Stewardship Programme has had a beneficial impact on the number of exposures reported to the National Poisons Information Service or their severity.
Automotive screenwashes may contain ethylene glycol, and/or methanol and/or isopropanol, or ethanol alone or in combination with the other ingredients. The concentrations and combinations of each constituent can vary considerably between products. Some products are sold ‘ready-to-use’ off the shelf while others require dilution in water at various ratios dependent on season. We conducted a study to investigate the toxicity resulting from exposure to screenwash as reported to the NPIS;7 some of the data have been reported previously in abstract.8,9
There were 295 enquiries involving 255 individual exposures. The majority (n=241, 94.5%) of exposures involved ingestion and 14 of these also involved other routes. Six cases were due to skin contact alone, 3 to inhalation alone, 3 to eye contact alone, 1 to ear exposure alone and another occurred from inhalation and skin contact. Children below 5 years of age accounted for 26% of all ingestions.
The identity (and therefore composition) of the screenwash was known with certainty in 124 of 241 ingestions and is shown in Table 1. Products included methanol in 106 formulations, isopropanol in 72, ethylene glycol in 38, and ethanol in 104.
|Table 1. Composition of screenwash products ingested.|
The Poisoning Severity Score was known in 235 of 241 cases of ingestion: most patients were asymptomatic (n=169, 71.9%), but 59 (25.1%) developed minor (PSS 1), 6 (2.6%) moderate (PSS 2), and 1 patient severe (PSS 3) features; this patient later died. Nausea (n=10), vomiting (n=11), abdominal pain (n=10), metabolic acidosis (n=8) and raised anion gap (n=8) were reported most commonly after ingestion.
In conclusion, most patients (71.9%) ingesting automotive screenwash did not develop features. The implication is that the amount of screenwash ingested was very small. The concentrations of ethanol in most screenwashes did not appear to impact potential toxicity. Skin and eye exposure produced either no features or only minor toxicity.
Reed diffusers are popular household air fresheners and comprise vessels and jars made of glass, containing fragrance liquid and 'wicking' reeds, which act to diffuse the scent of the liquid. In addition to essential oils, the liquid commonly contains glycol ethers (propylene glycol monobutyle ether, dipropylene glycol monomethyl ether, dipropylene glycol n-butyl ether and dipropylene glycol methyl ether acetate); other ingredietns and/or alternatives are 3-methoxy-3-methyl-1-butanol, petroleum distillates, ethanol and isopropanol.
Between 1 January 2010 and 31 December 2014, 754 patients were reported to the NPIS who had been exposed to reed diffusers; the majority (n=712) were children <5 years.10 Ingestion was the most common route of exposure (706 of 754 patients) and involved the liquid alone (n=570), water beads alone (n=84), sucking on the reeds (n=31) or ingesting the liquid and water beads (n=21).
The WHO/IPCS/EC/EAPCCT Poisoning Severity Score (PSS) was known in 702 of 706 sole ingestions: in 574 (81.3%), the PSS was 0 (asymptomatic); in 117 (16.6%) patients, the PSS was 1 (minor toxicity); in 11 (1.6%), the PSS was 2 (moderate toxicity); there were no patients with features graded PSS 3 (severe toxicity). Significantly (p=0.008) more patients became symptomatic (PSS 1 and PSS 2) following the ingestion of a reed diffuser containing 3-methoxy-3-methyl-1-butanol than propylene glycol monobutyl ether, though there was no significant difference when compared with those containing dipropylene glycol monomethyl ether (p=0.181).
The most common features following ingestion of fragrance liquid were nausea and vomiting (n=53), coughing (n=17) and CNS depression (n=9). Seven patients suffered eye exposure alone: two developed eye pain and four conjunctivitis. Dermal exposure alone was reported in six patients, two of whom developed skin irritation.
Despite the presence of chemicals known to cause CNS, respiratory, cardiac and ophthalmic toxicity, the majority of patients in our study developed no features or only minor symptoms following ingestion of reed diffuser fragrance liquid. Thus, we believe that the reason that the majority of children remain asymptomatic after reed diffuser exposure is because they do not ingest, or expose their eyes and skin to, sufficient quantities to elicit symptoms.
- Day R, Eddleston M, Thomas SHL, Thompson JP, Vale JA. Toxicity of soluble film automatic dishwashing products as reported to the United Kingdom National Poisons Information Service 2008-2015. Clin Toxicol 2016; 54:862-66.
- Day RC, Eddleston M, Thomas SHL, Thompson JP, Vale JA. How common are exposures to soluble film automatic dishwashing products in the UK? A retrospective UK National Poisons Information Service (NPIS) study conducted from January 2008 to October 2014. Clin Toxicol 2015; 53:314.
- Day R, Eddleston M, Thomas SHL, Thompson JP, Vale JA. Exposures to traditional automatic dishwashing tablets and a comparison with exposures to soluble film tablets reported to the United Kingdom National Poisons Information Service 2008–2015. Clin Toxicol 2016; online early: doi: 10.1080/15563650.2016.1264588.
- Williams H, Bateman DN, Thomas SHL, Thompson JP, Scott RAH, Vale JA. Exposure to liquid detergent capsules: a study undertaken by the UK National Poisons Information Service. Clin Toxicol 2012; 50:776-80.
- Williams H, Jones S, Wood K, Scott RAH, Eddleston M, Thomas SH, Thompson JP, Vale JA. Reported toxicity in 1486 liquid detergent capsule exposures to the UK National Poisons Information Service 2009–2012, including their ophthalmic and CNS effects. Clin Toxicol 2014; 52:136-40.
- Day R, Eddleston M, Thomas SHL, Thompson JP, Vale JA. The impact of an international initiative on exposures to liquid laundry detergent capsules reported to the United Kingdom National Poisons Information Service between 2008 to 2015. Clin Toxicol 2016; online early: doi: 10.1080/15563650.2016.1267359.
- Day R, Eddleston M, Thomas SHL, Thompson JP, Bradberry SM, Vale JA. Toxicity from automotive screenwashes reported to the United Kingdom National Poisons Information Service (NPIS) from 2012 to 2015. Clin Toxicol 2016; online early: doi: 10.1080/15563650.2016.1271130.
- Day RC, Bradberry SM, Eddleston M, Thomas SHL, Thompson JP, Vale JA. Toxicity resulting from automotive screenwash exposures reported to the UK's National Poisons Information Service from 2012 to 2014. Clin Toxicol 2016; 54:375.
- Day RC, Moyns E, Dougherty G, Eddleston M, Thomas SHL, Thompson JP, Vale JA. Composition of automotive screenwashes sold in the UK: how many contain ≥3% w/w methanol? Clin Toxicol 2016; 54:392-93.
- Panchal B, Eddleston M, Thomas SH, Thompson J, Vale A. 754 exposures to reed diffusers reported to the United Kingdom National Poisons Information Service 2010-2014. Clin Toxicol (Phila) 2016; 54: 333–338.
Information from recent publications and the NPIS Annual Report 2015/16.
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