The highest fine in Bulgaria for putting a product on the market that fails to comply with the EU regulation is 15,000 Bulgarian lev - just €7,670.

In France, the maximum fine is six months in jail and a €7,500 fine. In Italy, putting unsafe ski lifts or their components on the market could be punished with between six months and three years jail time, or a fine between €5,000 and €15,000.

The rules for safety of ski lifts and similar transport modes are laid down in an EU regulation that went into force in 2016.

It specifies safety requirements valid for the entire bloc.

However, determining the level of penalties for breaking the rules was then left up to the 28 individual member states.

"Member states shall lay down the rules on penalties applicable to infringements by economic operators of the provisions of this regulation and of national law adopted pursuant to this regulation," the regulation said.

It said that those penalties should be "effective, proportionate and dissuasive", but gave no further definition or method to quantify the criteria.

This way of phrasing penalty requirements is a common feature of EU law and has in the past led to a patchwork of fines in several areas of legislation: emissions cheating, internet access, and novel foods.

The 2015 case of emissions fraud by Volkswagen Group has spurred the commission into setting EU-wide level fines for the EU legislation on emissions cheating - but new bills in other areas where no scandal has happened, often still revert to the tradition of leaving it up to member states.

The picture of the ski lift sector came to light after this website requested the European Commission make public the letters in which member states informed the commission of their fines.

There is not only considerable variation between EU member states - which can lead to a race to the bottom and possibly even unfair competition - but questions also arise about how much of a deterrent such fines actually are.

One of Europe's largest cableway companies is the Doppelmayr-Garaventa group.

According to its most recent annual figures, it had €846m in sales revenues. Its competitor Leitner Ropeways had an annual turnover of €873m in 2017, while another such company, Poma, posted €345m in revenues that year.

If those companies were to break the EU safety rules - hypothetically - the fines they face would be nothing more than a rounding error on their balance sheets.

The regulation also covers safety components of the ski lifts and other cableways installations.

Because the EU is a single market, such components can come from everywhere in the bloc.

The risk is that firms with malign intentions could compare the potential risk of fines they run in the various EU countries, and set up shop in the place where the fines are lowest.

The EU commission has estimated that there were some 17,500 cableways installations in western Europe and the Alps, representing 60 percent of the world's total.

In 2009, 23 people were injured in Spain when a chairlift in Sierra Nevada malfunctioned. El Pais reported at the time that the accident was caused by fatigue in the materials.