LAS VEGAS (AP) — The federal government should shoulder much of the responsibility for cleaning up perchlorate that has tainted Lake Mead and water supplies for 20 million people, the company that produced the rocket-fuel ingredient near Henderson said in a letter to California Sen. Dianne Feinstein.
"The U.S. government remained the end-user for nearly all of the perchlorate produced at the plant until operations were discontinued in 1998," wrote George Christiansen, vice president for safety and environmental affairs for Kerr-McGee Corp., the Oklahoma-based parent company of the chemical plant near Henderson.
"Although the U.S. government therefore should be principally responsible for perchlorate found in groundwater affected by the plant, the U.S. government so far has refused to accept financial responsibility for the remediation work," Christiansen said in the letter delivered Friday to Feinstein, a Democrat.
On Jan. 3, Feinstein, in a letter to Kerr-McGee Chairman and Chief Executive Officer Luke Corbett, expressed "deep concerns" about the perchlorate contamination that has affected the Colorado River system in Lake Mead, and downstream in Nevada, Arizona and California.
She urged Corbett to accelerate the company's cleanup effort to remove the pollutant from groundwater that feeds the Las Vegas Wash. Nevada environmental officials estimate that 500 pounds per day of perchlorate, which affects the thyroid gland, flows into Lake Mead.
In a letter dated Thursday, Corbett told Feinstein that his company started working with state and federal environmental officials as soon as perchlorate was detected in the lake in 1997.
Feinstein's press secretary, Scott Gerber, told the Las Vegas Review-Journal Friday that the senator's staff had received the Kerr-McGee letters and were reviewing them.
Christiansen said in his letter that the plant near Henderson produced perchlorate for U.S. Defense and space programs. "The U.S. Navy oversaw the design and operations of the Henderson plant, and in fact, owned the site for more than 10 years."
The rocket-fuel oxidizer ammonium perchlorate had been produced for decades by Kerr-McGee and Pacific Engineering & Production Company of Nevada, another plant near Henderson. The PEPCON plant was destroyed by a series of explosions in 1988.
Christiansen also referred to a state-of-the-art ion exchange system that went on-line in late 1999 to extract perchlorate from groundwater seeping into a stream that flows into the Las Vegas Wash.
In two years, the company spent $61 million on its cleanup effort. It has augmented the process with a barrier system and a new treatment facility. Combined with the two other treatment sites, the company is extracting 850 gallons per minute of contaminated water at much higher concentrations than when the company began treatment in November 1999.
Todd Croft, an area supervisor for the state Environmental Protection Division, said a monitoring site on the Las Vegas Wash several miles downstream from Henderson shows about 500 pounds per day of perchlorate is entering Lake Mead. That's a marked improvement over the average in 1998 and 1999, when 816 pounds per day and 941 pounds per day, respectively, were passing the checkpoint.
Currently, Southern Nevada Water Authority officials are measuring perchlorate levels in both raw and treated water from Lake Mead at 14 parts per billion. One part per billion is the equivalent of a grain of salt in an Olympic-size swimming pool.
While the EPA has not set a safe drinking water guideline or maximum contaminant level for perchlorate, California has proposed a standard of about 6 parts per billion.
The EPA, meanwhile, continues to study the health effects of perchlorate in humans.
— Arizona Daily Sun