About 1.5 million homes and businesses in Florida and Georgia remained without power on Friday after Hurricane Irma roared through the state.

Federal and state officials said at a news conference that in some areas, getting the power grid back to typical capacity could take days or weeks.

"This is now the hard part. The recoveries are always difficult. This is going to be a long recovery," said Rick Perry, U.S. secretary of energy.

Two new cases of carbon monoxide poisoning from temporary generators made clear that dangers remained nearly a week after the powerful storm hit.

In Palm Beach County, a woman died and three men were in critical condition after authorities said carbon monoxide seeped in from a generator positioned just outside a home's garage on Thursday.

A family of four was also being treated Friday near Miami for exposure to the dangerous fumes from a generator outside their apartment.

Rick Perry

Federal Emergency Management Agency administrator Brock Long, right, looks on as Energy Secretary Rick Perry delivers an update Friday in Washington, D.C., on federal actions to support the response to Hurricane Irma. (Cliff Owen/Associated Press)

Protecting elderly residents

The state has also made urgent efforts to protect its vulnerable elderly residents after a string of deaths at a nursing home.

"They're more susceptible to the heat," Broward County commissioner Nan Rich said of the need to protect seniors.

"The thing that hits them first is dehydration, and then their temperature increases and then respiratory issues kick in. Then there's medication that needs to be refrigerated."

On Thursday, 57 residents were moved from a suburban Fort Lauderdale assisted-living facility without power to two nearby centres where electricity was just restored. Workers scrambled to keep patients cool with emergency stocks of ice and Popsicles.

Still, progress was being made. Statewide, only three nursing homes were still waiting for full power Friday night, according to the Florida Health Care Association.

Perry, who served over a decade as governor of hurricane-prone Texas, said the disaster response to Irma has been the best he's ever seen.

He hailed the efforts from both state and federal workers, as well as workers from 32 states and Canada who answered the call before the hurricane to help with the anticipated problems with the grid.

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Wood utility poles snapped by Hurricane Irma's high winds remain down on Thursday on Big Pine Key, Fla. Close to two million homes and businesses remained without power Friday after Hurricane Irma's path through the state. (Chip Somodevilla/Getty Images)

Acting Secretary of Homeland Security Elaine Duke said the goal now is to return people to their homes "as quickly as safety allows," but that the challenges are great, pointing to contrasts with Hurricane Harvey, which battered Texas and parts of Louisiana just before Irma's arrival.

Duke said the damage in Texas was more localized, while in Florida there have been reports of Irma damage in all 67 counties. As well, wind and not rain was the primary cause, unlike with Harvey.

Massive power outages

"That means homes are demolished, boats have been tossed around like toys, trees have been splintered," she said.

About 1.5 million homes and businesses in Florida and Georgia remained without power on Friday. Nearly 25 per cent of all customers in Miami-Dade County still don't have power.

Florida Power and Light officials earlier this week said that most customers on Florida's east coast would have their electricity restored by Sunday evening. They said it would take until Sept. 22 to get electricity back to the majority of customers in southwest Florida.

Tens of thousands of customers in Pinellas County on the state's west coast still don't have electricity as well.

'It's only Day 4 after Irma'

Brock Long, administrator of the Federal Emergency Management Agency (FEMA), said search and rescue efforts are wrapping up and now the challenge is to get affected residents on the road to recovery.

He estimated about 10,000 remain in shelters from a peak of 200,000 last week.

"We have a long way to go. It's only Day 4 after Irma," he said.

Long said finding transitional housing will require "innovative solutions," with officials aware of the shortage of trailers, and the issues in the past with trailers and cruise ships used after storms.

The ships seem to have been ruled out for all but "intermittent" shelter needs, such as for the emergency response workers who have been helping in the disaster recovery effort.

Hurricane Irma

Christopher Taylor walks through the flood waters from Hurricane Irma as his uncle's trailer is pulled out of the water on his family's land off Lake Shore Drive in Gainesville, Fla. (Brad McClenny/The Gainesville Sun/Associated Press)

The power issues zap air conditioning and refrigeration and also cause another dangerous headache: sewage overflows.

Local governments have submitted well over 100 "notices of pollution" to the state Department of Environmental Protection since Hurricane Irma struck, some involving multiple spills and releases of millions of litres of wastewater in various stages of treatment. 

"Floodwaters may contain not only bacteria from sanitary sewer overflows but other potential contaminants from agricultural or industrial waste," Environmental Protection Department spokesperson Dee Ann Miller said.

Nearly 23 million litres of wastewater were released from a plant on Virginia Key near Miami during a seven-hour power outage overnight Sunday that disabled its pumps — one of seven spills reported by the Miami-Dade County Water and Sewer Department. The water had gone through most of the treatment process but hadn't been chlorinated, spokeswoman Jennifer Messemer-Skold said.

Officials advised people not to swim at Miami-area beaches until waters could be tested for a variety of pollutants.

Hurricane Irma

Flood waters touch the bottom of a mailbox along in Bonita Springs, Fla., on Thursday, Sept. 14, 2017, four days after Hurricane Irma. (Nicole Raucheisen/Naples Daily News via AP Associated Press)

The U.S. Environmental Protection Agency deployed teams to help state officials assess damage to wastewater and drinking water systems.

Wastewater treatment is challenging enough in a state with flat, low-lying terrain and a booming population concentrated largely in coastal cities. Pipes and other infrastructure are aging and many residents use private septic tanks that are susceptible to flooding.

Too early to know scope of wastewater issue

Electricity interruptions during heavy storms often deliver the knockout punch to already vulnerable systems. They shut down "lift stations" pumping wastewater from lower to higher elevations on its way to treatment plants, causing backups that can propel untreated sewage into homes or through manhole covers onto city streets.

Some lift stations are equipped with emergency generators, while others are idled unless officials can get portable generators to them.

As of Wednesday, the Gulf Coast city of St. Petersburg had reported four spills. The largest, totalling about 1.65 million litres of partially treated wastewater, overflowed from a treatment plant holding tank Monday, while the others were at manholes.

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Flooding caused by Hurricane Irma is seen from a U.S. marine helicopter flying over storm damage near Fort Myers, Fla. (Jonathan Ernst/Reuters)

Other systems reported bigger spills — including 4.2 million litres of raw and treated sewage from the city of Oviedo and 5.7 million litres of effluent from a facility in Osceola County.

More than 125 systems in about 40 Florida counties advised residents to boil tap water before using it for drinking or cooking.

With files from Reuters and CBC News