Houston is the capital of the American oil industry; some in the industry even call it “Rome” since so much of the world’s energy business is done here.

So it’s not surprising that Houston-based oil employees would start to gather to make their voices heard as Congress considers climate change legislation — including cap-and-trade provisions, which would issue decreasing emissions allowances for industry and utilities, and then let companies trade their excess allowances. The concept is not popular with many in the industry.

A downtown theater in Houston is expected to be crowded today (live Web cast here) with oil company workers who will hear speakers claim that the Waxman-Markey climate change bill, already passed by the House, will destroy millions of American jobs, raise costs for consumers, and do little or nothing to actually reduce greenhouse gas emissions linked to global warming.

“It’s a dangerous piece of legislation,” James Hackett, chairman and chief executive of Anadarko Energy, which is busing employees to the event, told The Houston Chronicle.

Chevron invited employees and its retirees to the event as well, and is providing transportation, according to the newspaper.

Organizers say the event will be the first of many planned in 19 states in the coming weeks.

John Berger, the chief executive of Standard Renewable Energy, a Houston-based energy efficiency and solar company, said in a telephone interview this morning that the demonstrators needed to “calm down.”

“I don’t know what’s got into his Wheaties,” Mr. Berger said, referring to Mr. Hackett. “The next words I expect to hear out of him is that Texas should secede from the Union.”

However, Mr. Berger also said that the intensity of the opposition was in a way good news for alternative energy — because it means that it’s becoming big enough to worry about. “It’s getting conventional,” he said.

Corporate America, in fact, is divided on the bill, which passed the House in June, and will be considered by the Senate later this year.

Some corporations, including General Electric and Pacific Gas and Electric, have voiced support for it. And even the oil industry is not united. Shell has urged Congress to take action on climate change, and its executives have spoken out in favor of cap-and-trade.