Nov 21 (Reuters) - A grand jury has indicted Phillips 66

for illegally discharging hundreds of thousands of

gallons of industrial wastewater into Los Angeles County's sewer

system, and failing to report the violations to authorities.

The indictment against the Houston-based energy company

includes four counts of knowingly violating the federal Clean

Water Act and two counts of negligently violating that law, U.S.

Attorney Martin Estrada in Los Angeles said on Thursday.

Phillips 66 is expected to be arraigned in the coming weeks

in Los Angeles federal court.

It faces a maximum sentence of five years probation on each

count, and $2.4 million in fines.

Phillips 66 did not immediately respond to requests for

comment.

According to Wednesday's indictment, the discharges came

from Phillips 66's refinery in Carson, California.

In the first discharge, the refinery released 310,000

gallons of non-compliant wastewater, containing about 64,000

pounds of oil and grease, into Los Angeles' sewers over 2-1/2

hours on Nov. 24, 2020.

The oil-and-grease concentration was as high as 24,700

milligrams per liter, far higher than the 75 milligrams per

liter allowed under Phillips' permit, the indictment said.

In the second discharge, the refinery released 480,000

gallons of wastewater containing at least 33,700 pounds of oil

and grease, for a concentration of 12,900 milligrams per liter,

over six hours on Feb. 8, 2021.

Estrada said Phillips 66 acknowledged the discharges

only after being contacted by county regulators, and promised in

writing after the first discharge to "retrain operations

personnel" on how to manage and report discharges.