JUNEAU — The Alaska Senate on Wednesday delayed a vote on a bill that would change how the state regulates cruise ship wastewater.

The announcement came after at-times impassioned floor speeches and five failed attempts to amend HB80, including to give ships more time to meet water quality standards set out by a 2006 citizen initiative. Sen. Dennis Egan, D-Juneau, who proposed that amendment, said the cruise industry means a great deal to the region’s economy but he said he and others in his district have concerns about what impacts the bill may unintentionally have.

“It doesn’t take any ship out of the water so there’s nothing to fear, and it keeps clean water for the people who live here year-round,” Egan said of the amendment, which failed on a 7-10 vote with Egan and Sens. Bert Stedman, R-Sitka, and Peter Micciche, R-Soldotna, voting with the four minority Democrats.

The bill, proposed by Gov. Sean Parnell, would require that cruise ships discharge wastewater in a manner consistent with applicable state or federal law. It would strike the more stringent requirement that discharges meet state water quality standards at the point of discharge. The measure also would allow mixing zones where wastewater can be diluted into the water, if ships meet certain standards for treatment of discharge.

Critics charge the bill would reduce protections set out by the initiative; the chairman of the Alaska Democratic party has referred to it as “Parnell’s sewage bill.” Parnell’s Environmental Conservation commissioner, Larry Hartig, has said the proposal would align rules for cruise ships with those for others that get discharge permits from the agency.

Supporters also say the ships would remain held to high standards. Sen. Lesil McGuire, R-Anchorage, said that’s important for people to understand, and she said no member would vote to do anything that would jeopardize Alaska’s clean waters or salmon stocks.

Lawmakers in 2009 passed legislation allowing the department to temporarily let cruise ships have mixing zones. Hartig said companies at that time were not meeting the more rigorous standard set out by the initiative, at least for certain pollutants. That authority is set to expire in 2015.

That measure also called for a science advisory panel, which, in a preliminary report last year, found that none of the advanced wastewater treatment systems on ships operating in Alaska waters could consistently meet water quality standards at the point of discharge for “constituents of concern,” ammonia, copper, nickel and zinc. It also identified “little additional environmental benefit” to be gained by lowering the current permitted effluent limits to water quality standards at the point of discharge. The report said a dilution model, developed by an earlier panel, and other studies show concentrations lower than the water quality standards within seconds following discharge of the treated wastewater.

A marine ecologist who served on the panel, Michelle Ridgway, testified against the measure. She said she disagreed with several of the report’s findings and said she understood it would undergo further review before being finalized. Ridgway was in the audience during the Senate’s floor debate Wednesday.

Sen. Bill Wielechowski, his voice rising, said the bill was sold to lawmakers based on a report that isn’t final and wasn’t supposed to be final until 2015. Sen. Hollis French, D-Anchorage, said every time he heard the panel mentioned, he wanted people to know panel members were “misled,” told they would be allowed to finish their work and that the report wouldn’t be used as the basis for legislation.

Parnell spokeswoman Sharon Leighow said the administration strongly disagrees “with any assertion the department ever tried to mislead the Science Advisory Panel.”

“The panel was informed that their work could be considered in the context of changes to the law,” Leighow said in an email.

During a panel meeting in September, Lynn Kent, a deputy Environmental Conservation commissioner, said her department did not intend to make any changes to the panel’s report. According to meeting notes taken by a consultant and provided by the administration, Kent said the department would likely provide a report to the Legislature that would serve as a status update on the work of the department and panel. She said the Legislature might want a final report, or “to take action in the law.”

The panel’s report, marked preliminary, was dated in November. At the time of the meeting, the department “was not in a position to say what might happen in response to the Panel’s report in any definitive terms,” Kent said in an email Wednesday.

She said the panel’s report is not a draft report but a thorough review of the capability of existing treatment systems and of new and emerging technologies. Upon receiving the report, the department did not identify any outstanding issues for the panel to review, she said.

“HB80 is a logical next step to the regulation and management of cruise ship wastewater discharges,” she said. It doesn’t affect the department’s ability to continue to evaluate possible improvements in wastewater treatment or to require improvements to wastewater quality as new technologies that are effective and “economically feasible” emerge.

Senate Majority Leader John Coghill, R-North Pole, said the decision to push action on HB80 to next Tuesday was to allow senators who were absent Wednesday to have an opportunity to vote on the bill. Sens. Lyman Hoffman of Bethel, Gary Stevens of Kodiak and Donny Olson of Nome had excused absences.

The bill has already passed the House.