Detroit — Emma Lockridge often slips on a surgical mask at bedtime. She then piles pillows over her head and a blanket, hoping she'll get enough sleep.

Lockridge lives in southwest Detroit, just across the road from the Marathon Petroleum Co. refinery. It's a site that neighbors have long complained has compromised their health and quality of life.

"I want you to just imagine if you will be sleeping at 3:30 in the morning and all of a sudden you start coughing," Lockridge testified Monday before members of U.S. Congress and a packed audience inside Detroit's Kemeny Recreation Center.

"Then, your own coughing wakes you up, and you don't have a cold and your nose alerts you to the fact that there are chemicals in your bedroom, and you can't breathe, and they are toxic and they are choking you," she said. "This is no way to live."

Lockridge was part of a five-member panel of residents and environmental advocates called upon Monday to provide testimony at a congressional field hearing on air and water quality.

The hearing, focused on the disparate impacts of pollution on low-income communities and neighborhoods of color in Detroit and Flint, was hosted by U.S. Rep. Rashida Tlaib, D-Detroit, vice chair of the House Committee on Oversight and Reform Subcommittee on Environment, and Chairman Harley Rouda, a California Democrat.

"It makes me heartsick that the people of Detroit and Flint have been living without their basic rights, and that they have lost trust in elected officials’ commitment to preserving and protecting those rights," Rouda said in an opening statement.

Rouda, during the two-hour hearing, cited figures from the Detroit Community Health Assessment from last year, which noted that 38% of residents in the city live in poverty — the highest rate of any major U.S. city.

Infant mortality in the city is twice the rate of the rest of the state, children have elevated levels of lead in their blood, and the life expectancy of Detroit residents is lower than the statewide average in almost every neighborhood, he said.

Tlaib noted the 48217 ZIP code in Detroit is among the state's most polluted while in the shadow of the Marathon refinery.

Tlaib, who grew up in the neighborhood, told the crowd Monday "we have a right to breathe, and water is a human right."

"Entire generations grow up in sacrifice zones, where our air and water is polluted by wealthy corporations for profit, and we are expected to accept that," she said.

Tlaib’s first bill in Congress, the Justice For All Civil Rights Act, would expand U.S. civil rights protections to address "environmental racism" and other critical issues.

Monday's hearing comes after the refinery last week emitted a vapor that prompted an evacuation of the facility and worried residents. In February, a flare also malfunctioned there, emitting an odor that sparked fear across the community and several others nearby.

Tlaib raised concern over the latest issue at the refinery, saying residents are "still searching for answers."

David Leaver, general manager for Marathon, said the incident stemmed from a valve leak while the company was decommissioning some equipment. They are now working to determine what caused the valve to leak and assessing procedures to avoid future incidents.

The company, he said, acted quickly to notify authorities, shut the unit down and knocked down the vapors with water. Stationary and mobile air monitoring for hours after the incident turned up no problematic levels, he said.

Two contract workers were sent to the hospital. One was treated and released. The other is expected to make a full recovery and be discharged Monday, Leaver said.

In the face of criticism, Leaver noted Marathon has owned the facility for 60 years, and in the last two decades has reduced its emissions by 80%. It also has invested $350 million in the last eight years to lower emissions.

"We are part of the community. We breathe the same air that the community breathes," he said. "We as a company are doing everything we can to be an active member of the community."

Earlier Monday, residents and environmental justice groups sent a letter to the U.S. Chemical Safety and Hazard Investigation Board requesting a probe following the Thursday chemical release from the refinery.

Leaver, in response, said "we have nothing to hide" and that Marathon wants to have discussions on air quality with Tlaib, area businesses and others.

Officials with the state department of Environment, Great Lakes and Energy have said the agency is investigating Thursday’s vapor release and working with all parties to ensure public health and the environment are protected.

Nayyirah Shariff, director of the group Flint Rising, attended the hearing Monday to speak about the water crisis that's still plaguing residents of her hometown.

More than five years after the ill-fated drinking water source switch to the Flint River, residents there remain fearful.

"If there hasn't been a long-term plan developed to fix Flint, how can you fix any other community?" said Shariff, who spoke of how her water went from brown to yellow and smelled like "an open sewer."

Tlaib concluded the hearing Monday by telling attendees that this is just the start of federal lawmakers' efforts to bring change.

"We, at the federal level in Congress, need to do more, and we know that," she told the crowd. "I just want you to know that this makes us feel like 'we have to move quicker.' How many times do we need to study the fact that we're dying?"

cferretti@detroitnews.com