Chemical, electrical and production engineers are among those who gather every Friday for a service at the Muslim Association of West Texas, a small mosque in Midland, Texas.

According to Farook Rafeek, who regularly attends these services, more than half of the congregation works in the oil industry.

And Trump’s new immigration ban may keep the mosque from growing: despite an oil industry desperate for specialists like the ones who moved across the world from majority-Muslim nations to work in Texas, fewer are on the way.

“The Trump administration is already having an impact on hiring decisions,” said George Stein, managing director at Commodity Talent, a recruiting agency for oil companies. “Two of our international clients are considering basing foreign hires outside of the United States because of difficulties arising from the ban.”

After Trump’s first executive order to bar some travel to the United States was blocked by courts, Trump issued his newer, somewhat narrower order on Monday. Under the conditions of this second order, people from Iran, Sudan, Somalia, Libya, Syria and Yemen would not be able to travel unless they receive case-by-case waivers for “significant business or professional obligations”.

Announcements of the two versions of the ban – and the accompanying rhetoric – are also already undercutting recruiting options within the university system. Michael Webber, deputy director of University of Texas’ Energy Institute, said last week a graduate student from Iran lost a job prospect because of the company’s concern over his visa. Webber said the university is also reconsidering allocation of funding for future students, which might keep top talent from the ban’s six named countries from moving to the United States. “We can’t give $100,000 to an Iranian here if we don’t know if they can get a job afterwards,” said Webber. “Our student mix is going to change.”

Most of the Muslims at the mosque in Midland have green cards, but say the anti-Muslim undertones of Trump’s ban make moving to the United States unappealing for job-seeking Muslims still living abroad. “Canada is looking good. So is Germany,” said an electrical engineer in Midland from Pakistan, who asked to remain anonymous over job concerns. “When you come here you feel like you’re giving up your honor just to get set up.”

The specter of an immigrant brain drain coincides with Trump’s promise of massive deregulation, a paradox which puts oil companies in a tricky spot: they want to remain attractive to a broad hiring pool, but don’t want to ruffle a friendly administration. After Trump’s first immigration executive order, for example, Chevron issued a statement asserting its commitment to inclusion without explicitly condemning the ban. “The political priorities are changing,” said Webber. “I keep joking oil and gas will go Democratic in a decade.”

If Trump’s immigration ban clears court hurdles and is fully implemented, experts say it would have a dramatic impact across the industry. “It would be damaging industry-wide,” said oil and gas consultant Mark LaCour. LaCour explained the industry already faces talent shortages and has for years: frontiers in the industry such as “downstreaming” (using petroleum to manufacture everything from plastics to paint brushes) require experts. “Especially around new technologies. Cognitive science or big data, for example. A portion of those scientists are Muslim,” said LaCour.

Oil companies already compete with tech firms in Silicon Valley for cognitive science and big data specialists. With the ban in place the two industries will be competing for even fewer immigrants candidates. “Oil is already competing with tech,” said Webber. “Things just got a little bit harder.”

Though some Muslims around the United States have been recent targets of hate crimes, Rafeek and other worshippers at the mosque in Midland feel safe. “Living in west Texas one thing I’ve noticed is that, whatever is going on in the media, whatever the rhetoric is of Donald Trump, People are very nice to me. People are kind to me.” said Izzah Saleemi, an electrical engineer.

More than a century of steady, global growth forced the oil and gas industry to learn such tolerance, but an inclusive approach to hiring hasn’t been around forever. “Oil has a black mark going way back. Fifty, 60 years ago it was famous for being antisemitic,” said Webber. “But they can’t afford that. They need capital and people from around the world.”