SAUGUS – An early-morning, three-alarm fire at 3 Waterwheel Lane Sunday caused $800,000 in damage to the house and sent two firefighters to area hospitals for dehydration and other minor injuries.A man and a women renting the house, Carol Blenda Reyes-Avila and Wade B. Lee, managed to escape unharmed after hearing smoke detectors go off at 5:09 a.m., Saugus Fire Chief Don McQuaid said. However, their three dogs and five cats were still missing as of Sunday night.Investigators from the state fire marshal and State Police were on scene to determine the cause throughout the day Sunday. Jennifer Mieth, spokeswoman for the fire marshal, said Sunday night the cause of the fire was still under investigation. McQuaid estimated the $800,000 damage to be the entire value of the home. Capt. Thomas Nolan said all rooms burned to the ground.Reyes-Avila said she is concerned about the welfare of her animals. McQuaid said firefighters, who were actively digging through burnt pieces of the house, are still searching for the animals.?The roof and second floor collapsed, so it?s difficult to find them,” McQuaid said. “There is still a detail at the scene, continuing through Sunday night.”McQuaid said multiple units from several cities and towns, including Lynn, Everett, Malden, Melrose, Lynnfield and Lexington, Chelsea, Wakefield, and Revere, were dispatched. Nolan estimated 40 firefighters were on scene.McQuaid said all firefighters from the surrounding towns and cities did a great job, despite muggy conditions.?It was 75 degrees at 5 a.m.,” he said, checking the temperature on his phone. “We were extremely warm and muggy, even before we put on our gear. Saugus did a great job, and I want to thank out-of-town firefighters for all of their help.”Neighbors on scene said their alarms went off due to the heavy fire and smoke.