I was alarmed when I read about toxic-waste collection company Cramoil Singapore being issued a stop-work order by national water agency PUB this month for discharging toxic wastewater into public sewers (Toxic-waste collection firm ordered to stop work; April 26).

This was not Cramoil's first offence.

In fact, it had committed 20 similar offences since 2010 and was fined a total of $52,500.

What is more disturbing is that this company is supposed to be collecting toxic industrial wastewater to prevent harm to the public, but had instead been disposing of it in a way that would cause harm.

Why was Cramoil Singapore allowed to continue operating despite so many offences over the last eight years?

Is it the only company that can provide such a service in Singapore?

Shouldn't a penalty heavier than a fine be imposed on repeat offenders that deliberately put the health of the public at risk?

It is obvious that financial penalties have not been effective in this case.

Perhaps a jail term for the people responsible should be considered.

Nancy Teo Geok Har (Madam)