The San Francisco Fire Department has reminded the public why all fireworks are illegal in the city, ahead of July Fourth celebrations, with a video from June 30 showing “just how fast” fires caused by pyrotechnics can spread.The video was recorded in MacLaren Park and shows a firework landing on the grass there. Seconds later, sparks ignite and fire starts spreading.Local media reported that three acres were burnt in the incident. The fire was “quickly contained” by the fire department, they said.The fire department reminded locals that “all fireworks in San Francisco, including the so-called safe and sane fireworks, are illegal” because they cause “countless injuries, hundreds of thousands of dollars in property damage, and, in some cases, deaths.” Credit: San Francisco Fire Department via Storyful