The agreement was signed just days before President-elect Donald Trump takes office, potentially putting the breaks on thawing relations between the two former Cold War adversaries.
At a ceremony at Havana's iconic Hotel Nacional, Jeffrey De Laurentis, charge d'affaires at the US embassy in Cuba, and Eduardo Rodriguez, Cuba's deputy Transportation Minister, signed the document promoting joint response to the clean up of oil spills or other toxic waste.
"This bilateral agreement is an acknowledgement of the importance of protecting our marine ecosystems and coastal communities from pollution caused by oil spills and other hazardous substances," said De Laurentis.
He added the pact is yet another step forward in bilateral efforts to normalize ties after half a century of hostile relations.
"Establishing a mutual framework -- including diplomatic, legal and technical elements -- to prevent, prepare for and respond to oil spills in the marine environment is particularly important for neighbors only 90 miles (144 kilometers) apart," he said.
Rodriguez echoed those statements, saying "we will work together to fully implement the agreement, which is a positive contribution to the process of normalizing relations between the two countries."
The two countries have worked together to prevent oil spills in these areas since 2011, he noted.