Lawyers for a Texas natural gas company convicted of illegally storing mercury in Rhode Island have told a judge he should limit its fine to no more than $50,000 after the U.S. Supreme Court struck down the original $18 million penalty.

Southern Union Co. on Monday argued before U.S. District Court Judge William Smith that a jury found the company violated the law for one day. The maximum penalty is $50,000 per day.

Prosecutors say Southern Union broke the law for more than two years. Smith based his $18 million penalty in part on that number. The high court found he shouldn't have done that without a jury deciding the number of days the company broke the law.

Prosecutors asked Smith to seat a new jury to help decide a new penalty.