About 5,000 barrels of a diluted form of heavy Canadian crude oil spilled from a 22-foot rupture in the Pegasus pipeline in Mayflower, Ark. Operator ExxonMobil Pipeline said it had removed nearly all of the free-standing oil and had shifted efforts to long-term remediation.
The company said in a community newsletter sent to Mayflower residents and published on its website Saturday "all chemicals, or chemicals of concern," were below levels considered a threat to human health.
Student activist group Citizens Advisory Group and Global Community Monitor said residents showed signs of exposure to chemicals ranging from benzene, a carcinogen, to toluene, a central nervous system depressant, more than four weeks after the spill.
ExxonMobil Pipeline admitted to finding levels of benzene and other harmful chemicals in early samples taken at Mayflower. It said air and water quality was within safe limits in the weeks following the spill.
A 27-page report from the Arkansas Department of Environmental Quality indicates trace amounts of chemicals present in some water samples taken in June.