A blaze broke out at Rainham Mark Grammar School in the early hours of this morning - destroying the science block.
Firefighters battled against thick black acrid smoke to stop it spreading to other buildings at the school in Pump Lane.
It is believed it was sparked by a faulty battery tester in the laboratory.
Head teacher Simon Decker said: “I can’t thank the fire crews enough. They were here within three minutes and averted what could have been a real disaster as we keep a lot of chemicals in rooms near by.”
Twelve firefighters from Medway wearing breathing apparatus used a special fan to pump air into the block to prevent an explosion.
Don't miss out, subscribe today. Keep up to date with our newsletters.
A guide for your future. For year 11 students in Kent and Medway. Click here for the e-edition.
Education, Training & Childcare is a special supplement published by KM Media Group four times a year. Click here for latest e-edition.
Get the latest food and drink news, recipes from some of the nation's top chefs plus updates from Kent's vineyards and breweries.
Search in your local area to find your perfect partner in Kent, with FreshStart Dating! PLUS, register for free!.
Find out what's going on in the garden, with Kent expert Lucy Hewett's weekly update.
Buy pictures that you've seen in a KM newspaper, or send in a picture and we will place it on our photo sales website so that you can purchase a super, unique gift.