Exxon said about 5,000 barrels of oil was released last month from a 22-foot rupture on its Pegasus pipeline in Mayflower. The pipeline, built in the 1940s, was carrying a diluted form of Canadian crude oil, dubbed oil sands, at the time of the spill.
Air samples taken March 30, the day after the incident, indicated high levels of compounds considered harmful to human health. The samples were conducted by a student activist trained by the Faulkner County (Ark.) Citizens Advisory Group and Global Community Monitor.
"Total toxic hydrocarbons were detected at more than 88,000 parts per billion in the ambient air and present a complex airborne mixture or soup of toxic chemicals that residents may have been exposed to from the Mayflower tar sands bitumen spill," Neil Carman, a representative from the Texas chapter of the Sierra Club, said in a statement.
Exxon 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, however.
The report, published by the activist groups, said residents are showing signs of exposure to chemicals ranging from benzene, a carcinogen, to toluene, a central nervous system depressant, more than four weeks after the spill.
There was no response from Exxon on the report.