In 1987, nearly 200 countries ratified the Montreal Protocol, which sought to ban the chemicals responsible for depleting the ozone layer, the protective layer enveloping the Earth. The protocol mandated the phase out for all the major ozone depleting substances, including chlorofluorocarbons, halons and less damaging transitional chemicals such as hydrochlorofluorocarbons, and is widely considered one of the most successful environmental treaties ever signed. New research published in the journal Atmospheric Chemistry and Physics, however, suggests that increasing emissions of ozone-destroying substances that are not regulated by the protocol are threatening to affect the recovery of the layer. The new threat to the ozone layer is dichloromethane, which uses include paint stripping to agricultural fumigation and the production of pharmaceuticals, and has increased by over 60% in the past decade. The study found that the substance weren’t only present at ground level, and if it reaches the ozone layer in significant quantities is could cause damage to the layer. To find out more check out A growing threat to the ozone layer from short-lived anthropogenic chlorocarbons.