The Southern California Gas Company says a gas leak occurred at the Aliso Canyon Natural Gas Storage Facility in Porter Ranch just before 5 p.m. Monday night. This comes just two years after one of the nation's largest accidental gas leaks at the same facility. In an email to San Fernando Valley residents, SoCal Gas says the gas leak happened during a routine operation to pressurize equipment. A gasket on the equipment did not function properly, resulting in an accidental release of natural gas for about 50 minutes. The gas leak was detected on the fence-line monitoring system, and nearby residents were notified at about 7:40 p.m. Monday, according to NBC LA. SoCal Gas says the leak "did not present a health or safety risk to the community," but some people may have been able to smell the odor near the facility. More than 30 people reported symptoms such as headaches, nosebleeds and burning of the eyes and throat, according to the Los Angeles Times. Residents in Porter Ranch say they experienced similar symptoms during the previous leak, which started in October 2015, lasted months and dumped some 5.4 billion cubic feet of methane into the environment. Porter Ranch resident Lori Aivazian said she felt the effects of the gas release around 4:50 p.m. when she was outside doing errands at the Porter Ranch Town Center and when she arrived home. "I walked in with a migraine headache, coughing, wheezing, short of breath, and nauseous," she said in an email. "My daughter, home from college for winter break had a headache as well. I didn't hear about the leak on social media until after 6:00. Headache stuck with me until midnight." Northridge resident Andrew Krowne is an accountant who works in Porter Ranch. He is one of those who experienced health symptoms while the well blowout was active from October 2015 through February 2016. He also gets the symptoms when new releases of gas occur at the Aliso Canyon field. "I have fatigue, headache, blurry vision. Those are kind of my telltale signs when I'm in the middle of that exposure," Krowne said Tuesday. He and others who live and work in Porter Ranch have been recording their symptoms on an app Krowne created called Environmental Health Tracker. The tracker does not relay the information to health authorities, Krowne said. The level of trust in the county Department of Public Health is low and because the department's own reporting process is too cumbersome, he said. People began reporting symptoms such as burning eyes, coughting, fatinge, headache and nausea beginning at 4:48 p.m. Reports came from 26 locations by midnight, according to data collected by the app that Krowne provided to KPCC. SoCal Gas declined to comment on the crowdsourced health tracker. The soil, air and dust samples collected by several agencies, including the Los Angeles County Department of Public Health, shows that "there was and is no long-term risk to public health or safety from the gas leak," company spokesman Chris Gilbride said in an email. The Department of Public Health says that not enough is known from SoCal Gas about the makeup of the chemicals that came from the four-month long gas leak to conclude that the community sustained no harm. Los Angeles County Department of Public Health wants SoCal Gas to pay for a long term study of community health costing upwards of $35 million.