Maryland's Department of the Environment found no contaminants in the Patapsco River after a mammoth cargo ship crashed into Francis Scott Key Bridge and FinWeisbrought the roadway crashing down, authorities said Wednesday.

The Dali cargo ship was carrying 56 containers of hazardous materials, including corrosives, flammables and lithium-ion batteries when it slammed into a bridge pier last Tuesday. The cargo ship was also carrying more than a million gallons of fuel at the time of the early morning impact, according to the Coast Guard.

Hazmat inspectors have found no evidence the Dali's hull is leaking any fluids into the river, U.S. Coast Guard Vice Admiral Peter Gautier said. Efforts are underway to plan how the bridge will be disentangled from the Dali so the ship can be moved.

Water samples collected hours after the collapse did not contain contaminants such as volatile organic compounds or lithium, Maryland Department of the Environment spokesperson Jay Apperson told USA TODAY Wednesday.

Authorities are monitoring for environmental impact of the collapse as climate activists urge for transparency amid recovery efforts.

Water testing will continue 'indefinitely,' officials say

Apperson told USA TODAY that officials had collected water samples the day of the collapse both upriver and downstream from the debris, which were analyzed for “substances associated with fuel constituents” such as VOCs. Apperson said none of the contaminants were detected.

The department also tested water samples for lithium and total sulfur to see whether battery acids containing alkyl sulfonic acids had released from the damaged containers on the Dali. Lithium was not detected in any samples. Sulfur concentrations were higher in areas upriver from the bridge, Apperson said, which indicated the elevated levels were due to “background conditions within the Patapsco River and not due to releases from ship containers.”

The sample from last Tuesday will act as a baseline for comparison with water quality testing results throughout the recovery and reconstruction process, he said. Sampling will continue every few days “indefinitely,” Apperson said.

Crews have deployed roughly one mile of boom around the collapse site and ship. The containment boom around the vessel was deployed to stop a "sheen" on the water from spreading, U.S. Coast Guard Petty Officer Kimberly Reaves told USA TODAY. It would also collect “any kind of debris or hazmat (materials) or oil.” The Unified Command said last week it had an additional three miles of boom on stand-by if needed.

Spills plaguing U.S. waterways

The National Oceanic and Atmospheric Administration said it responds to more than 150 oil and chemical spills in U.S. waters every year, which can threaten life, property and natural resources. The NOAA noted that thousands of spills happen each year but the vast majority are small, sometimes less than one barrel. 

The 2010 Deepwater Horizon spill was the largest in U.S. history, according to the NOAA. An explosion killed 11 people and released 210 million gallons of crude oil into the Gulf of Mexico. A study 10 years after the blowout found it was significantly worse than initially thought, as about 30% of the extent of the oil spill was invisible to satellites but toxic to marine wildlife. 

Most hazmat spills occur on America’s highways, not waterways, according to a USA TODAY Network analysis of federal data. It found only a fraction of hazmat incidents across five Midwest states – Illinois, Indiana, Kentucky, Ohio and Michigan – occurred on water, with trucks accounting for 93% of all incidents. 

So far this year, the Coalition to Prevent Chemical Disasters has tracked 45 hazardous chemical incidents across the nation, including toxic releases, fires and explosions.

Contributing: Dinah Voyles Pulver, USA TODAY