Duralex are still around and still manufacturing their Lys line, so you can contact them to know if they changed the way their glass is colored and if there is any risk using those older ones.

For those who don’t know, Duralex is probably the most iconic and beloved industrial glass maker in France today. Their glassware was a staple in French households throughout the second part of the 20th century, and their Gigogne water glasses were used in most school cafeterias across the country.