The Selangor environment department discovered the illegal activity during an operation yesterday.

The water in Sungai Aur had turned blue from leftover chemical waste in the drums.

Selangor environmental director Nor Aziah Jaafar said hundreds of used drums were found. “They were ready to be cleaned in an open area. Blue water was also found in a drain outside the premises that led to a large drain nearby.”

Nor Aziah said the chemical was categorised as scheduled waste with the code SW409 and the cleaning was carried out without the approval of the department.

A man in his 40s was detained to help in investigations. Samples of the water was also collected for analysis.

Nor Aziah said a total compound fine of RM500,000 was issued for various environmental offences.