Threatening letters sent this week to banks and financial institutions declare "It's payback time" and promise death within 10 days, according to the text of the message released Thursday.

More than 50 letters mailed to Chase Bank branches and federal regulatory offices in 11 cities this week, most filled with white powder, have so far tested negative for any dangerous toxins.

But the FBI says the hoax is still a serious crime and is investigating the letters as a possible extreme backlash to the nation's financial crisis.

"Steal tens of thousands of people's money and not expect reprercussions," says the letter, which is written in all capital letters and includes the misspelling. "It's payback time. What you just breathed in will kill you within 10 days. Thank (name redacted) and the FDIC for your demise."

The FBI would not identify the person whose name was deleted. The FDIC stands for the Federal Deposit Insurance Corp.

Authorities said the letters appear to be from the same source, and were focusing on possible suspects near Amarillo, Texas, where the envelopes were postmarked.

Since Monday the letters have been opened in the offices of Chase Bank branches, the FDIC and the U.S. Office of Thrift Supervision, which regulates all federal and many state thrift institutions. They were sent to offices in or near 11 cities: Atlanta; Chicago; Columbus, Ohio; Dallas; Denver; Newark, N.J.; New York City; Oklahoma City; Phoenix; San Francisco and Arlington, Va.

An FBI spokesman said letters sent to Oklahoma were filled with harmless calcium.

The U.S. Postal Inspection Serpresident takes office, she said.

Arkansas contributes about 1 percent of the national total of greenhouse gases that cause global warming, according to the nonprofit Center for Climate Strategies that conducted studies for the commission.

The commission recommends Arkansas reduce its greenhouse gas emissions below 2000 levels by 20 percent by 2020, 35 percent by 2025, and 50 percent by 2035. The result, if other states do their parts, would return the climate to stable levels currently recognized by the scientific community, according to the center.

"One has to look at the bigger picture," Webb says. "When you look at everybody's one percent and two percent and five percent, that's what adds up to the total. Just because ours is smaller doesn't mean that we don't contribute to the problem and can't contribute to the solution."

In Arkansas, as in other states, electricity production and consumption along with the everyday use of cars and trucks are the major contributors to global warming. But Arkansas' extensive forests act as a "carbon sink," absorbing some of the vast quantities of carbon dioxide released into the atmosphere each day. The commission recommendations are aimed at every sector that can add or subtract to this bigger picture.

Among the recommendations are an endorsement of nuclear power, a ban on new coal-fired power plants until technology is available to capture and bury carbon emissions, a sales tax exemption on the purchase of energy-efficient household appliances, the conversion of municipal solid waste into heat, steam or electricity, a study on converting government vehicles to plug-in electric hybrids, the reforestation of marginal farmland, and the use of electricity generated by solar, wind, geothermal, biogas or hydropower.

Other recommendations include the establishment of a center to monitor the effects of climate change on Arkansans, a requirement that electric companies supply a percentage of electricity from renewable energy sources, rebates for the purchase of fuel-efficient vehicles, tax incentives for businesses to develop renewable energy systems, energy audits for homeowners, and energy-conservation programs for low-income Arkansans.

The center looked at the cost to implement 29 of the 54 recommendations, and estimated a cost of $3.7 billion over 17 years

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