The new Building Canada Strong Act contains a list of measures that Prime Minister Mark Carney says will get projects moving faster in the face of major threats to Canada's economy from U.S. President Donald Trump.

But experts warn Bill C-39 could also dismantle environmental safeguards that protect Canadians and prevent wildlife from extinction, despite the federal government claiming otherwise.

"It greatly saddens me that in standing up to bullying from the United States, we are willing to put some of the things that make Canada so special on the table," said Gretchen Fitzgerald, executive director of the Sierra Club Canada Foundation.

When he tabled Bill C-39, government House leader Steven MacKinnon called it one of the most important economic pieces of legislation in a generation, adding that its purpose is to make project decisions in one year.

Tucked inside are a dizzying array of more than 300 clauses that amend more than a dozen separate pieces of federal legislation, including laws to protect species at risk, water quality and fisheries. Not to mention proposed changes to the Labour Code, which have upset unions.

CBC News combed through the bill's more than 200 pages and spoke with environmental and resource development experts about its impact. Here's a detailed look at what's inside. Shovels before science?

Typically before construction can begin on projects like mines, railways and ports, the environment and climate change minister needs to sign off on an impact assessment review — a thorough evaluation of a proposed project's potential environmental, social, economic and health effects.

Under the new bill, Ottawa could grant permits for preliminary construction before the Impact Assessment Agency of Canada completes its work — if the environment minister considers it "enabling activities" and in the "public interest." It would still maintain the right to stop a project if an impact assessment determines it should not go forward. The federal government insists the environment won't be harmed.

"We are not rolling back our environmental regulations," said Environment and Climate Change Minister Julie Dabrusin.

But critics say the proposed legislation will claw back environmental protections, and that its vague wording asks the public to place too much trust in the government's interpretation of the bill.

"I want to see evidence that our government understands what the national interest is because I think it's in our national interest not to poison our lakes and rivers," said Megan Leslie, president and CEO of World Wildlife Fund Canada.

"I think it's in our national interest to have safe communities when it comes to floods and fires.… It's in our national interest not to have species go extinct." Heather Exner-Pirot, director of energy, natural resources and environment at the Macdonald-Laurier Institute, said the proposed legislation responds to the needs of industries to build faster. "Overall, it's very positive," she said.

Exner-Pirot also said early construction will be done in narrow exceptions, such as minor work before winter.

"Canada's construction season is very constrained," Exner-Pirot said. "And so if you can get something done … you can save months and millions or tens of millions of dollars on the project." Henry VIII powers The bill also makes permanent controversial sweeping powers in the Building Canada Act, Bill C-5, which the government passed last year promising they would be temporary.

Under C-5, Ottawa can exempt certain projects deemed in the national interest from a wide set of environmental regulations and acts of Parliament. Academics and critics accuse the government of inserting Henry VIII clauses, a reference to the autocratic King Henry VIII of England.

Alberta's West Coast pipeline and the Robert Banks Terminal 2 port expansion in B.C.'s lower mainland are on track to obtain this treatment.

Experts say proposed Labour Code change spell legal trouble Carney says he has a 'very clear mandate' to push through big changes These powers were supposed to last five years. But C-39 removes that sunset clause. Exner-Pirot said people shouldn't be worried.

"Any Parliament can revoke laws that were made in the previous Parliament," she said.

"If the people think it's being abused, then there will be an incentive for future governments to change that." Preapproval of projects over large regions This new bill also expands the "project of national interest" concept to create entire regions of national interest.

For this to happen, the government would need to conduct an environmental assessment of the region under consideration. One is currently underway in the Ring of Fire, a mineral-rich and ecologically sensitive area of northern Ontario.

Following such a study, cabinet would then be able to designate the entire area a region of national interest, giving Ottawa broad authority to approve future activities. But federal officials told reporters the activities must adhere to specific types and criteria which Ottawa will outline when granting the designation.

For example, Ottawa could say that mining for critical minerals in the Ring of Fire is permitted along with any roads, bridges and high-voltage power lines, but a natural gas pipeline may not be allowed to go through the same area.

Environmentalists worry the government is putting speed and shareholders over survival of sensitive wildlife species and habitat.

"It's essentially the Building Canada Act on steroids," said Julia Levin, associate director of Environmental Defence Canada, calling the regions "sacrifice zones where projects could get rubber stamped." But regions of national interest could also offer a path to advance renewable energy projects. A regional assessment has been completed for wind development offshore of Nova Scotia.

The 300,000-square-kilometre study area could unlock significant sustainable power generation for the province and the country.

"In some ways, for those who wanted to see clean energy projects and electrification and decarbonization fast-tracked, that's more possible than ever under this act," said David Wright, an environmental and energy law professor at the University of Calgary. But Wright said even clean energy projects come with risks to people and the environment.

"That could come at the expense of the rights and interests of Indigenous Peoples, ecosystems, species at risk and private landowners," he said.

Easier to drain lakes, dump in waterways Bill C-39 keeps intact protections for species at risk, but experts say it also has loopholes.

Proponents already have the ability to dump stones, gravel, rubbish and other material in rivers. They can even drain lakes. But as it stands, they have to get the approval of the federal cabinet.

"What this power allows the minister to do is exempt those water bodies so that there's no more oversight," said Anna Johnston, a staff lawyer with West Coast Environmental Law.

This could be a problem, she and others note, in places like northern Alberta where oilsands companies use considerable amounts of water. The proposed legislation would also amend the Species at Risk Act (SARA).

A provision known as the "jeopardy test" was kept intact after academics wrote an open letter and environmentalists launched a media campaign opposing its removal. But the ministers of fisheries and environment would still be able to consider "technical, economic and practical" considerations when permitting construction in sensitive areas.

Environmentalists say this waters down the key protection measure, which prohibits any project from going forward if it could drive a wildlife species extinct.

"That's really backwards thinking," said Lisa Gue, a national policy manager with the David Suzuki Foundation. "Unravelling these standards actually leaves our country vulnerable to missteps that could cause long-term damage and harm to communities.… It looks like nature is going to be steamrolled." Fish habitat potentially at risk Similarly, the bill proposes changes to the Fisheries Act, which could allow projects to harm fish and fish habitat if it's not economic or practical to protect them.

Ottawa is proposing to make up for the possible damage through an expanded fish habitat bank regime that proponents could pay into for restoration, but the bill doesn't say how that would work.

Margot Venton, a lawyer and director of the nature program at Ecojustice Canada, is worried about ecosystem collapse, which could lead to fishery closures, like that of the cod industry in Newfoundland during the early 1990s.

AFN chief warns Carney against 'abusing' majority to pass new major projects bill Carney government to study new major projects bill with tool last used in Harper era "We don't have an economy over the long term if we destroy the ecosystem," Venton said. After reviewing the proposed legislation, Sally Otto, a professor in the department of zoology at the University of British Columbia, said the government is willing to draw Canada's environmental deficit down deeply into the red to balance the country's finances.

"I'm all for building Canada strong, but we also need to build Canada safe," Otto said. "Safe for the environment, safe for humans, safe for nature."