With a week to go until Election Day, a gusher of Texas oil money is flowing once more into California to support Proposition 23, the ballot measure that would suspend the state’s global warming law.

Tesoro and Valero, the Texas oil companies that are largely funding Prop 23, contributed $1.5 million to the campaign on Friday. It was the first seven-figure donation since Sept. 2, when the billionaire Koch brothers dropped $1 million into campaign coffers, according to California Secretary of State records.

But in the intervening months, when contributions from the petrochemical industry dwindled mostly to a few five-figure donations, the No on 23 campaign revved up its fundraising efforts and now has taken in more than $30 million to the Yes forces’ $10.6 million.

Just in the last few days, San Francisco-based utility Pacific Gas & Electric has given another $250,000 to the No campaign while teachers and public employees unions donated a combined $300,000. (Tellingly, even an East Coast power company with coal-fired power plants in its portfolio, AES Corp, donated $25,000 to the No campaign on Friday.)

Also in the last couple of days, $500,000 has been given to No campaign committees targeting low-income and minority voters, which some strategists consider crucial to defeating Prop 23.

California’s climate change law, known as AB 32, requires the state to cut greenhouse gas emissions to 1990 levels by 2020. Prop 23 would suspend AB 32 until the state unemployment rate — currently at 12.4 percent — drops to 5.5 percent for four consecutive quarters. That has happened only three times in the past 40 years.

A new player in the No campaign is the California League of Conservation Voters and its sister organization, the League of Conservation Voters. The groups’ campaign committee has raised $4.2 million, including a $200,000 donation from a managing director at Goldman Sachs in New York. The main No on 23 campaign has transferred $1.9 million to the committee in recent days, according to finance records.

“CLCV and LCV are contacting several hundred thousand California voters who are likely to support environmental values, explaining Prop 23 and asking them to vote no (either through absentee ballot or on Nov. 2), and turning out the vote on election day,” Jenesse Miller, a spokesperson for the California League of Conservation Voters, said in an email. “Our campaign is a combination of phone calls, slate cards and other mail pieces.”

In a sign that the No forces may be feeling increasingly confident — a new Los Angeles Times/USC poll released Monday found Prop 23 losing by a wide margin — the League of Conservation Voters committee has been funneling money to other ballot initiatives important to environmentalists and green technology investors and entrepreneurs.

For instance, the committee has given more than $600,000 to defeat Proposition 26, a ballot measure supported by the oil, tobacco, and alcohol industries that would reclassify environmental impact fees as taxes and require a two-thirds vote of the state legislature to impose them rather than a simple majority.

Green groups and AB 32 supporters fear Prop 26 could cripple efforts to levy fees to implement the global warming law.