Before the Environmental Protection Agency started regulating pollution in the nation's air, water, and land, things were dire. These photos show how bad it was.

We've made significant progress since then, but there's still a lot of work to do to keep our environment and those who live in it healthy.

The Trump administration's EPA aims to roll back a number of environmental protections, though Scott Pruitt resigned on July 5 amid ethics scandals.

The new acting administrator of the EPA, Andrew Wheeler, is likely to continue with a similar agenda.

Now that Supreme Court Justice Anthony Kennedy has announced his retirement, many experts think a number of environmental regulations could get overturned.

As the story goes, the chemical-filled Cuyahoga River in Cleveland burst into flames on June 22, 1969, possibly ignited by a spark from a passing train.

That had happened at least dozen times before on the Cuyahoga. Additional fires were known to blaze up on rivers in Detroit, Baltimore, Buffalo, and other cities.

River fires were far from the only environmental disasters in the US at the time. A spill from an offshore oil rig in California coated the coast in oil and pollutants. Smog and car exhaust choked cities around the country.

In the late 60s, Americans were growing more aware of how unregulated pollution and chemical use were endangering the country and the people in it. People were ready for a change.

In his 1970 State of the Union address, President Richard Nixon said: "We still think of air as free. But clean air is not free, and neither is clean water. The price tag on pollution control is high. Through our years of past carelessness we incurred a debt to nature, and now that debt is being called."

Nixon followed that up with a list of requests to Congress and later that year announced the formation of the Environmental Protection Agency, or EPA.

Soon after it was founded, the EPA began a photo project called Documerica that captured more than 81,000 images showing what the US looked like from 1971 to 1977. More than 20,000 photos were archived, and at least 15,000 have been digitized by the National Archives.

The EPA's role since then has varied from administration to administration.

Trump's former EPA administrator Scott Pruitt worked to roll back a number of rules that were previously put in place to protect air and water. Many reports suggested Pruitt's primary aim was to eliminate most environmental protections and dismantle parts of the regulatory agency.

But on July 5, in the wake of a long list of scandals, Trump announced he'd accepted Pruitt's resignation.

Pruitt had announced plans to kill the Clean Power Plan, the Obama administration's main initiative to fight climate change by lowering emissions. Under Pruitt, the EPA also reversed a ban on a pesticide that can harm children's brains and moved to rescind the Clean Water Rule, which clarified the Clean Water Act to prohibit industries from dumping pollutants into streams and wetlands.

Andrew Wheeler, a former coal lobbyist, was Pruitt's deputy and is now acting administrator of the EPA, so it's likely that he will pursue a similar agenda.

The resignation of Pruitt, along with the retirement of Supreme Court Justice Anthony Kennedy, raises new questions about the future of environmental regulations in the US. Kennedy, who plans to finish his work on July 31, was the swing vote in a number of environmental cases, including the one that granted the EPA the ability to regulate greenhouse gases under the Clean Air Act. A new Trump nominee may be more likely to overturn key environmental protections, according to legal experts.

As a reminder of what the US looked like before many of the EPA's policies were in place, here's a selection of the Documerica photos from the 1970s.