Complaints were presented that gasoline marketed by a large refiner had caused filter problems at retail filling stations and customer vehicles. A class action lawsuit was filed against the refiner for replacement of filters and tanks. Baker & O'Brien reviewed the gasoline production and testing records, and opined on the contamination source.

Refiners take great precautions to ensure that every gallon of gasoline reaching consumers meets stringent product quality specifications. Occasionally, however, an upset in refinery operations can result in off-specification product being unknowingly delivered into the downstream distribution system, affecting retailers and/or consumers. In such cases, quick identification and correction of the source of the problem is essential.

A large refiner-marketer received complaints of filter problems at both gasoline retail sites and in consumers' vehicles. Initial investigations identified "caustic entrainment" as the likely source of the problem. During refining, gasoline components are sometimes "washed" with an aqueous caustic solution to remove potentially harmful sulfur compounds. The caustic solution forms a separate aqueous phase which is removed by gravity settling. On rare occasions, if too much caustic is used, the aqueous solution may form an emulsion and become "entrained" (i.e., carried along) with the gasoline. This entrained material can sometimes contain small quantities of dirt, rust, and grime as it moves through the distribution system, causing reduced fuel flow (or even plugging) through filters designed to protect against such materials. It is not always possible to detect low levels of caustic entrainment through routine product sampling.

A class action lawsuit was filed against the refiner for replacement of filters and tanks. Baker & O'Brien was engaged as an expert to review the gasoline production and testing records, to identify the source of the contamination, and to explain what steps the refiner had taken to prevent such future incidents. An expert report was prepared and a deposition taken. The refiner settled with the plaintiffs prior to trial.