"Old or Abandoned Wells Are Key Sources of Water Contamination"
"New oil and gas drilling is probably the most visible activity people associate with threats to groundwater in Texas. But it's not usually the source of known contamination, according to state records.
Instead, old or abandoned oil and gas wells, petroleum storage facilities and even existing water wells are most frequently identified as problems.
A Texas Groundwater Protection Committee report, presented to the Legislature last year, said there were 4,729 active groundwater contamination cases documented or under enforcement in 2008."Source: Fort Worth Star-Telegram, 09/07/2010