Check for country of manufacture: Some older Pyrex pieces were made in the United States. If you find vintage Pyrex with a "Made in the USA" marking, it is likely to be from the era when borosilicate glass was used.
Read product descriptions: When buying Pyrex cookware online or from a store, carefully read the product descriptions or labels to see if they mention the type of glass used. Some retailers might specify whether the product is made from borosilicate glass.
Research specific product lines: If you are concerned about a particular Pyrex product line, try searching online for reviews, recalls, or any reported issues related to that specific line. Keep in mind that while rare, product recalls or safety concerns can happen with any brand.
Handle with care: Regardless of the type of glass, handle all glass cookware with care, avoiding extreme temperature changes and using appropriate precautions when cooking or storing food.
Since my information might be outdated, I recommend checking for any updates or safety information related to Pyrex glassware from reliable sources such as the manufacturer's website or consumer product safety agencies.