Liquid radioactive waste from Devonport dockyard could in future be discharged by pipeline out to sea.
Environmental campaigners are concerned about the discharges
The waste comes from work on Trident nuclear submarines at the navy base.
Last year DML was authorised to discharge the radioactive material into the River Tamar.
But environmental groups criticised the decision.
Now the Environment Agency (EA) is considering 11 options, including sea dumping.
Other options include storage on site, boreholes, and using barges to transport the waste out to sea.
EA nuclear regulator Anil Koshti said it was always keen to look at possible environmental improvements.
Devonport dockyard refits Trident nuclear submarines
He said: "The current method is completely acceptable.
"It meets all the environmental and health and safety requirements.
"But there were a number of issues raised during consultation last year and some of them asked about discharging by pipeline.
"So as a condition of the authorisation, we asked DML to produce a report considering these options."
He said the Environment Agency would now be considering the options.
He also pointed out that the amount of radioactivity discharged was very low compared with normal background radiation.
"We receive about 4,000 units of background radiation in Devon and up to 7,000 in Cornwall, what you get from DL is less than 0.1 unit."
The EA would be making its conclusions "in due course".