Negligent Landlord, Multiple Sewage Backups.

Location: Indiana

I am currently living in a rental home in Indiana that has experienced repeated raw sewage backups. The backups have occurred 7 times in the past 3 years, 4 of which happened this year alone. My landlord has not permanently resolved the underlying issue and has never hired a professional remediation company to properly clean and sanitize the contaminated areas.

The sewage backups have been caused by the property's sewage lift station failing.
When the lift station fails, raw sewage, including toilet paper and feces, backs up through the floor drain in the finished basement

The basement is finished meaning the sewage entered a living space rather than an unfinished basement. During one of the backups sewage entered the furnace through the condensate drain. The furnace filter became wet from the sewage contamination. To my knowledge the furnace has never been professionally sanitized, inspected for sewage contamination, or replaced.
Because of concerns that operating the HVAC system could circulate contaminants throughout the home we have gone without air conditioning following the most recent sewage backup.

Although “cleanup” has occurred after the backups, my landlord has never hired a professional sewage remediation company to disinfect and remediate the affected areas, furnace included even though the sewage came up from the floor drain in the utility closet where the furnace is located. I am concerned that proper sanitation procedures were never followed after repeated contamination by raw sewage.

My lease contains a broad liability and indemnification clause that attempts to limit my landlord's liability for injuries and property damage arising from many different causes including plumbing failures, accidents, and even certain instances of the landlord's own negligence. But based on my understanding the lease provision doesn’t completely eliminate my landlord’s legal obligation to maintain a safe and habitable environment. I could be wrong so I’m wondering how that works.

Any advice would be greatly appreciated.