(Bloomberg) – Key lawmakers started a push Monday forCongress to provide emergency disaster funds for Texas, as thescale of damage from Hurricane Harvey becameapparent.

"We will need to put together an emergency supplementalappropriations bill," RepublicanJohn Culberson, a senior member of the House spending panel whorepresents Houston, said in a Bloomberg Television interview. "Noone could have ever predicted or expected a catastrophe of thismagnitude to descend on the Houston area."

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Culberson was joined by House Minority Leader Nancy Pelosi ofCalifornia in calling for a bill. Pelosi made clear that any billshould be exempt from budget caps that require offsetting spendingcuts.

"Republicans must be ready to join Democrats in passing a timelyrelief bill that makes all necessary resources available throughemergency spending," Pelosi said in a statement.

It's not clear yet whether Republican leaders would back such abill or when it would come to a vote.

$1.8B available for immediate needs

So far, the Trump administration hasn't determined whetheradditional funds will be needed, actingHomeland Security Secretary Elaine Duke said Monday onBloomberg Television. She said if additional funds are needed, theDepartment of Homeland Security will work with Congress to obtainthem.

A House Republican aide said that the Federal EmergencyManagement Agency had $1.8 billion available for immediatedisaster needs as of Friday, adding that amount is sufficient, fornow. FEMA also has the authority to shift money into its disasterrelief fund from other accounts.

A deluge of rain and rising floodwaters has left Houstonimmersed. Tropical Storm Harvey, which made landfall as a category4 hurricane, has drifted back toward the Gulf of Mexico and ispoised to regain strength before crashing ashore again, this timeon the Texas-Louisiana border.

500,000 may be eligible for assistance

Harvey's cost could reach $30 billion when including the impacton the labor force, power grid, transportation and other elementsthat support the region's energy sector, Chuck Watson, a disastermodeler with Enki Research, said in an email Monday. That wouldplace it among the top eight hurricanes to ever strike the U.S.David Havens, an insurance analyst at Imperial Capital, said thefinal tally might be as high as $100 billion.

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Vice President Mike Pence said that as many as a half-a-millionpeople may be ultimately eligible for assistance.

Adding a Harvey spending bill onto Congress's busy Septemberagenda could affect efforts by Republican leaders to pass a stopgapspending bill by Sept. 30 to prevent a government shutdown and toraise the nation's debt ceiling.

Funding for Harvey relief, for example, could be used to win thevotes of the 36-member Texas House delegation for a stopgapspending bill or a debt limit measure.

Republicans divided on disaster spending

The Republican Party, however, has been divided in the past overwhether disaster spending needs to be offset by other domesticspending cuts, a debate that could return over Harvey responsefunding.

Both of the Republican senators representing Texas, John Cornynand Ted Cruz, voted against a $50 billion Superstorm Sandy spendingbill in early 2013 after pushing for spending cuts to be attached.Cornyn and Cruz say they voted "no" in the end because of unrelatedspending attached to the package.

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Representative Peter King, a New York Republican, lashed out atCruz on Twitter Saturday over his Sandy vote.

"Ted Cruz & Texas cohorts voted vs NY/NJ aid after Sandy butI'll vote 4 Harvey aid. NY wont abandon Texas. 1 bad turn doesntdeserve another," King tweeted.

A conservative push to stop any Harvey aid that adds to thedeficit could also complicate a GOP push later in the year forsteep tax cuts that add to the deficit.

Down payment on hurricane relief?

Congress may also decide to provide a quick down payment onhurricane relief, followed later by a more comprehensive package.In 2005, Congress approved $10 billion in immediateHurricane Katrina aid while most members were still on Augustrecess. A $51 billion follow-up package was approved months later,after House conservatives, including Pence, fought unsuccessfullyfor spending cuts to offset the cost.

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Pence on Monday told KHOU-TV in Houston that the White House is"very confident that the Congress of the United States is going tobe there to provide the resources necessary," to help Texasrecover. He didn't mention spending cuts.