AUSTIN, Texas (AP) — Exxon Mobil Corp. has reported inadvertent emissions of large amounts of pollutants at its flagship refinery near Houston.

Officials at the Baytown refinery reported a leak in a heat exchanger tube on Tuesday prompted them to shut down a flexicoking unit that separates heavy oils into fuels.

In their report to the Texas Commission on Environmental Quality, the officials reported that the shutdowns resulted in releases of hydrogen sulfide, nitrous oxide, sulfur dioxide and carbon monoxide exceeding the plant's permit limits.

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  • Top 10 Most Polluting Countries

    We look at which 10 countries have the most CO2 emissions. Figure are preliminary 2010 numbers from the U.S. government's <a href="http://cdiac.ornl.gov/trends/emis/perlim_2009_2010_estimates.html" target="_hplink">Carbon Dioxide Information Analysis Center. </a> (Photo Getty Images)

  • #10 - Saudia Arabia

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 493,726 (Photo MARWAN NAAMANI/AFP/Getty Images)

  • #9 - Canada

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 518,475 (Photo MARK RALSTON/AFP/Getty Images)

  • #8 - Korea

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 563,126 (Photo CHOI JAE-KU/AFP/Getty Images)

  • #7 - Iran

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 574,667 (Photo FRED DUFOUR/AFP/Getty Images)

  • #6 - Germany

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 762,543 (Photo JOHANNES EISELE/AFP/Getty Images)

  • #5 - Japan

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 1,138,432 (Photo YOSHIKAZU TSUNO/AFP/Getty Images)

  • #4 - Russia

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 1,688,688 (Photo KIRILL KUDRYAVTSEV/AFP/Getty Images)

  • #3 - India

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 2,069,738 (Photo ROBERTO SCHMIDT/AFP/Getty Images)

  • #2 - USA

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 5,492,170 (Photo by Kevork Djansezian/Getty Images)

  • #1 - China

    Estimated CO2 Emissions in 2010 (in thousands of metric tonnes): 8,240,958 (Photo PETER PARKS/AFP/Getty Images)