The new policy is in keeping with current prohibitions against smoking tobacco products on MTS vehicles or facilities.
"The popularity of electronic cigarettes has grown significantly in recent years," MTS Chief Executive Paul Jablonski said. "We now have uniform policy between the way we treat traditional cigarettes and electronic cigarettes."
The ban will go into effect July 18. The agency said fines will be $50 for the first offense, $75 for the second offense and $100 for subsequent offenses.
The amended ordinance prohibits passengers that "smoke or carry a lighted or smoldering pipe, cigar, cigarette, or tobacco or use any electronic smoking product or device that causes smoke, mist or vapor in any form."
The North County Transit District has a similar prohibition, as do many transit agencies across the state. The city and county of San Diego also have amended their codes to treat vapor inhalers like traditional cigarettes.
E-cigarettes have become popular as an alternative to smoking tobacco products, but concerns have been raised about health risks, particularly for nearby people impacted by secondhand fumes.
Faith leaders and concerned San Diegans are gathering Friday night in San Ysidro for a major show of support for migrant families at the border.
A man suspected of threatening deadly violence while robbing three San Diego-area banks over the last two weeks was indicted by a grand jury Friday on a slate of federal charges.
On Friday, more pups across the country will join their masters at the office, gym and other businesses for the 20th annual Take Your Dog to Work Day.
There is controversy over a TIME Magazine cover showing a crying toddler superimposed next an image of President Trump.
Hoover High School took a trip into the past by opening a time capsule from 1978. The capsule was dug up in a construction project several years before it was meant to be unearthed.
On Friday, President Trump mistakenly mentioned the mayor of San Diego when talking about immigrants being tipped off about immigration raids.
A judge denied a motion to dismiss charges against a Rancho Bernardo man accused of drinking himself to sleep and passing out with a lit cigarette, causing a fire in his condominium that killed his two children.
U.S. Sen. Kamala Harris Friday toured the Otay Mesa Immigration and Detention Facility, where she visited migrant mothers who were separated from their children in what the California Democrat called "a crime against humanity being committed by the U.S. government."
On the first day of summer, the San Diego County Water Authority unveiled a new outreach program that highlights the value of safe and reliable water supplies for the region.