Brokers have allegedly been smuggling in adulterated chemicals to supply them to the wholesalers in Hatkhola and BMA Bhaban on Topkhana Road since the restriction was slapped in March after over 100 people died from drinking methanol for addiction about four years ago in Gaibandha and Narsingdi.

The majority of diagnoses, mostly biochemistry and histo-pathological tests, are highly likely to give incorrect or false conclusions, including microscopic examinations to confirm biopsy of tissues as in the case of cancer.

The concern came to a head after a series of wrong diagnostic tests was detected. A patient in a leading diagnostic centre in Dhanmondi tested positive for urine infection and the same person got a negative test result from a research laboratory after he went there to reconfirm the test.

A biopsy test for suspected cancer at a diagnostic centre was positive, but a second examination confirmed that the patient had tissue damage, not cancer. Another patient at a Dhanmondi laboratory tested positive for thyroid cancer, but a second test showed a negative result.

"We use ethanol, methanol, acetone and toluene for chemical reaction called staining in biochemistry and histo-pathology laboratories. If low-grade chemicals are used with reagents, the possibility of getting a false outcome is almost 99 percent which is a dangerous practice," said a biochemist of a research laboratory.

According to the Import Policy 2003-06, only pharmaceutical companies and a few other relevant users like research laboratories can import ethanol, methanol, acetone, diethyl ether, potassium permanganate, chromic acid, carbolic acid, acetic anhydrite, toluene and other chemicals. But commercial use is prohibited.

On the issue, Dr ABM Haroon, managing director of Samorita Hospital, said, "I wrote to the Drug Administration to allow limited import for all diagnostic centres in Dhaka but did not get any response."

"We also face similar problems and have no option but to use whatever chemicals are available," an official of the Popular Diagnostic said.

A lab technician, asking not to be named, told The Daily Star: "We use low concentration diluted chemicals. Biochemists or pathologists will never approve substandard chemicals, but we use them as the chemicals turned scarce."

"The restriction has led to widespread smuggling of chemicals and use of low-grade products. Before the restriction, diagnostic centres received a smooth supply of high-standard chemicals," said Hasan Ahmed, a leader of Bangladesh Scientific Dealers Association in Hatkhola. "Many traders have resorted to sales of impure chemicals to diagnostic centres and clinics."

A chemical trader in BMA Bhaban said: "We don't have pure chemicals and sell impure ones in secret to only known clients."

A visit to Hatkhola Market home to more than 150 chemical traders revealed that most of them are selling adulterated chemicals.

A 2.5 litre bottle of original methanol sells at Tk 6,000 which is now scarce, but a bottle of adulterated substance is available at Tk 1,200-2,200 depending on concentration.

Hatkhola and BMA Bhaban are the only places in Bangladesh that sell chemicals wholesale.

"Only rarely clients prefer pure chemicals. Most of them buy adulterated ones for their diagnostic centres or hospitals. At least five laboratories regularly buy adulterated chemicals from us," a trader said.

The Department of Narcotics Control (DNC), assigned to check the illegal business, has apparently ducked their duty.

DNC Director General Kamaluddin Ahmed said: "We monitor only the licensed users of the chemicals and it is not always possible to track illegal traders."