FILE - In this March 29, 2013, file photo, workers tend to a well head during a hydraulic fracturing operation outside Rifle, in western Colorado. Two new rules intended to ease tensions over fracking in Colorado will have limited impact, affecting only about 1 percent of the drilling in the state, according to an analysis by state regulators. The Colorado Oil and Gas Conservation Commission is to hold hearings starting Monday, Nov. 16, 2015, on proposals designed to address complaints that arise as Colorado’s growing suburbs and oilfields collide. (AP Photo/Brennan Linsley, File)

DENVER | Only four of the estimated 500 oil and gas companies operating in Colorado say they can’t meet the April 1 deadline to implement new safety rules to limit spills during major floods, according to regulators.

In this March 29, 2013 file photo, workers tend to a well head during a hydraulic fracturing operation at an Encana Oil & Gas (USA) Inc. gas well outside Rifle, in western Colorado. The Obama administration is proposing a rule that would require companies that drill for oil and natural gas on federal lands to publicly disclose chemicals used in hydraulic fracturing operations. The new "fracking" rule replaces a draft proposed last year that was withdrawn amid industry complaints that federal regulation could hinder an ongoing boom in natural gas production.  (AP Photo/Brennan Linsley, File)

The rules require such precautions as remote shut-off devices for wells and installing anchors to help keep tanks from toppling in floodwaters. They apply to facilities within a government-designated 100-year flood plain, the area that would be inundated by a so-called 100-year flood — a deluge so strong the odds of it occurring in any year are 100-to-1.

The Colorado Oil and Gas Conservation Commission imposed the rules after a 2013 flood along the Front Range caused the release of 48,000 gallons of oil and 43,000 gallons of polluted water.

The flooding killed 10 people and caused $3 billion in damage. Nearly 2,000 homes were damaged or destroyed.

Companies had until Feb. 1 to ask for a waiver or extension to the rules. Chevron Production Co., Extraction Oil & Gas, Peterson Energy Operating Inc. and PDC Energy Inc. requested more time to retrofit more than 200 wells, tanks and other facilities, commission documents show.

In some cases, the companies plan to shut down the affected facilities but are awaiting permits from another agency. In others, companies said they just learned that redrawn flood plains now include more of their facilities.

The commission hasn’t acted on the requests.

It’s not clear how many facilities are covered by the rules. The commission estimated in 2014 that more than 5,900 wells were within 500 feet of a waterway big enough to have a name, but flood plains don’t necessarily conform to that 500-foot margin.

The rules were not controversial compared with other regulations in Colorado, such as the minimum distance between wells and houses and air-pollution controls.

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