EPA Takes Action After Subcontractor Altered Measurements In Sampling For Groundwater Contamination Resulting From Norfolk Southern Train Derailment

On March 2, the U.S. Environmental Protection Agency sent a notice to Tetra Tech Inc. detailing the failure of its subcontractor—ALS Houston—to meet data quality standards in groundwater sampling conducted at the Norfolk Southern train derailment site in Ohio in the fall of 2025. 

Rigorous and ongoing validating analysis confirms there is no ongoing exposure to toxic chemicals from the derailment endangering the public health or environment in East Palestine.

In September 2025, as part of this quality assurance and quality control process, EPA identified potential discrepancies in groundwater sampling data from the government’s contractor for 2-butoxyethanol, a colorless solvent used in household cleaners, paints, varnishes, and paint strippers.

EPA found that the results analyzed by the government subcontractor, ALS Houston, showed the presence of 2-butoxyethanol that did not match the results from split sampling testing at other labs. 

Under EPA's oversight and after extensive confirmatory testing, in February 2026, EPA’s contractor, Tetra Tech, notified the agency that ALS Houston had in fact altered measurements—which resulted in the false sampling data—and as a result terminated two analysts for failure to follow standard operating procedures. 

Because of EPA’s investigation and quick action, none of the falsified data was used to make any health, safety, cleanup, or enforcement decisions at the site. 

Past and current data indicate there is no risk to groundwater from 2-butoxyethanol in East Palestine.

Click Here for the EPA announcement.

[Posted: March 3, 2026]  PA Environment Digest