Number 239 (Story #2), September 8, 1995 by Phillip F. Schewe and Ben Stein THE OZONE HOLE CONTINUES TO DEEPEN. Ground-based measurements of the total amount of ozone above the Halley research station in Antarctica showed 10 years ago that springtime (October) ozone levels were persistently falling and were well below historic levels. A new report from the same site adds another decade's worth of data, testifying to a continuing decline of ozone each October and extension of the depletion period on into the Antarctic summer (January and February). The researchers presenting the new data point out that compliance with controls over manmade emissions of chlorofluorocarbons (the biggest cause of ozone loss) should result in a stratospheric chlorine peak in the late 1990s, after which (it is hoped) ozone recovery would slowly ensue. However, only by the middle of the 21st century would chlorine levels be as low as they were when the ozone hole was first discovered. (A.E. Jones and J.D. Shanklin, Nature, 3 August, 1995.)