: Flush the tank with clean water until all traces of chlorine and detergent are gone. Best Practices :
A worker enters the tank to scrape, wash, or pressure-clean surfaces. While sometimes necessary for heavy sludge or tank inspections, manual cleaning is the most dangerous method. Regulations like OSHA’s confined space standard (1910.146) heavily restrict it, requiring lockout/tagout, atmospheric testing, rescue plans, and PPE.