Orlando, Fla. -- Sixteen cruise lines have signed a voluntary agreement with the Florida Department of Environmental Protection (DEP) to curb dumping. The agreement includes 13 items, ranging from how ships dispose of ash, recycle glass and remove sewage. For example, ships now will recycle fluorescent lights instead of throwing them away to stop mercury contamination in aquifers.

Each ship involved has agreed to limit waste disposal to 100 kilograms per month and withhold dumping wastewater until they are four miles offshore, according to officials.