The dirty secrets of a huge fatberg discovered lurking under the seafront of a Devon town have been laid bare after scientists carried out an “autopsy” of the monster.

As expected, household cooking fats, wet wipes and other hygiene products were key components of the 64m-long beast (bigger than the Leaning Tower of Pisa) but it also contained bits of bone, twigs, string – and false teeth.

Happily, it did not contain any detectable levels of toxic chemicals, and the scientists who examined lumps of it could not apportion blame for it to any particular businesses, neighbourhoods or groups. It appears to have been very much a community effort.

False teeth were among the things found in the fatberg. Photograph: University of Exeter/PA

The fatberg was discovered under The Esplanade in Sidmouth, a few metres from the sea, by South West Water just before Christmas last year and made headlines around the world.

In February a hardy bunch of workers donned breathing apparatus to begin the painstaking process of hacking the fatberg into small pieces and removing it from the sewer. It took eight weeks and the monster was carted away in 36 tankers.

Quick Guide What not to flush to avoid contributing to fatbergs Show Campaigns to educate people about how not to feed fatbergs take pains to remind us that toilets and sinks are not “magic portals”. There is a simple set of rules for the bathroom: stick to flushing the three Ps: pee, poo and (toilet) paper. Everything else – sanitary towels, nappies, cotton buds, condoms, dental floss, used plasters and whatever else you might think to chuck down the toilet – should go into the bin. Just because a product says it is flushable doesn’t mean that it is biodegradable. Baby wipes might be a godsend to parents, but not to Victorian-era sewerage systems. Wipes marketed as flushable will probably be able to make their way down your toilet, but will eventually clog up the pipes further along their journey. The kitchen is another area of concern. Water companies are keen to bust the myth that running hot water and pouring washing-up liquid down the sink ahead of fats, oils or grease will stop it building up and blocking the pipes. Their recommendation is to keep a small container, such as an old margarine tub, to hand in your kitchen, into which you can pour oil and fat before safely disposing of it in the bin. Martin Belam

A team of scientists from the University of Exeter were given the scarcely less enviable job of carrying out the autopsy to establish how it came into being and whether it posed environmental risks.

The scientists were given four 10kg samples from the fatberg, which smelled like a heady combination of rotting meat and an unclean toilet. They melted the chunks and then combed through them by hand before subjecting samples to forensic analysis.

The team found that the samples they received were mostly made of animal fats consistent with domestic food preparation combined with household hygiene products such as wet wipes and sanitary products, as well as natural and artificial fibres from toilet tissues and laundry.

Crucially, the team found the fatberg contained no detectable levels of toxic chemicals, meaning its presence in the sewer did not pose a chemical or biological risk to the environment or human health.

Prof John Love, a synthetic biology expert at the University of Exeter, said: “We worried that the fatberg might concentrate fat-soluble chemicals such as those found in contraceptives, contain now-banned microplastic beads from cosmetics and be rich in potentially pathogenic microbes, but we found no trace of these possible dangers.

Items scientists found in the fatberg. Photograph: University of Exeter/PA

“We were all rather surprised to find that this Sidmouth fatberg was simply a lump of fat aggregated with wet wipes, sanitary towels and other household products that really should be put in the bin and not down the toilet. The microfibres we did find probably came from toilet tissue and laundry, and the bacteria were those we would normally associate with a sewer.”

Scientists from the Greenpeace laboratory, based at the university’s Streatham Campus, also looked at the chemical composition of the fatberg. The results suggested that the fats found were more in keeping with domestic food preparation than commercial food outlets, while the chemicals were those found in personal care products rather than pharmaceuticals or pesticides.

Nicky Cunningham, the manager for the Centre for Resilience in Environment, Water and Waste, said: “The results indicate that there isn’t a single contributing factor or demographic responsible for this fatberg coming to being.”

South West Water’s director of wastewater, Andrew Roantree, said: “Although we deal with around 8,500 blocked sewers every year, the Sidmouth fatberg was by far the largest discovered in our service history. We wanted to learn as much as we could about it, how it was created and what it was made of to help us avoid further fatbergs in future.

“We will be using these results to help us educate, inform and change the behaviours of people in terms of what they are putting down the toilet and sink. That’s not just applicable to Sidmouth but across our region.”